This thread is full of clever insight useful for anyone who is interested in making recipe tweaks for their own modpacks. I would like the conversation to also include ideas about balance, progression, and stuff like that.
That sounds like it would deserve its own thread, but absolutely a topic of discussion when discussing 'grind'.
As a mod pack dev, I don't often make any recipe tweaks, since that is generally something I prefer to leave to the mod devs themselves. However, there is an extensive amount I do within the config files that has a significant impact here that I can address.
Before we start on yet another wall o' text, I'd just like to state for the record that the following is my own personal opinion and should not be taken as any kind of objective statements or demands.
Balance is a tricky term. You have to pick a balance point, and go from there. Generally, what I do is pick a mod, or perhaps a small set of mods, that I use as my 'fulcrum', my litmus test if you will, and balance around them. For example, in my current pack, I'm using the Team CoFH mod suite as my fulcrum, and the tech in the mod is balanced around the concepts and costs found in that mod. This is made significantly easier by having other mods adopt CoFH-dependent recipes that I can flag in the config files, like MFR's. From there, rather than altering other mod's recipes, I look at the recipes themselves and think 'if this were a CoFH machine, would the resource cost of this machine match what it does?'. For example, I have found that in most instances, EnderIO balances on a very similar scale to CoFH, and I very rarely have any concerns on that topic.
Balance is more than just resource investment, it is also tedium. CoFH gates certain tech behind certain machines, but largely, until you start getting into alloying, you don't have any significant time-sinks involved with crafting, outside the refining of the raw materials themselves. Sure, it's got some sub-combines, but unlike -some- mods, don't have consumable components like, say, a hammer with only eighty uses before you have to make a new one that is used in crafting a very common component. Ahem. And you don't have to sit on your keister and wait for a machine to spin up and make things that you are waiting on right now. Ahem.
EnderIO has more alloys, and they are more important in low to mid level construction components, so you've got more potential for a time-lag waiting on an alloy to smelt up for a recipe. However, they are also fairly intuitive alloys, and once you make them, you don't have to do anything else with them. You don't have to wait for a series of machines, each one performing its own time consuming task, for something to be completed. Sufficiently advanced planning can give you enough alloys to get you through your current project.
Which leads us to the next point: progression.
In Thermal Expansion, progression is clearly delineated by the machines needed to produce something. Getting reliable access to Invar, for example, kicks you up a tier in components. Anything requiring Hardened Glass requires the Induction Smelter. Anything that requires molten or liquid product is probably going to need the Magma Crucible. These machines are gates that are needed to pass to get to the next tier. But once those machines are up, you are good to go.
EnderIO has a similar alloy-based tier system, however their tier components also have material requirements which can prove troublesome. Some alloys require ender pearls, some require glowstone. Some require both. There's a second tier of alloys that requires the first tier to craft. But it all is done with the same machine. So instead of needing Machine X to pass the gate (other than the original one for the Alloy Furnace and SAG Mill itself), you need certain components in quantity to advance.
Here's where a lot of people want to tinker, and can become a hotly contested point of contention. Being able to bypass a tier 'gate' can result in 'early access to' something. There are some who would go so far as to call this an 'exploit', and something to swing at with a nerf-bat at the very least. And as you increase the number of mods, the number of possibilities to bypass a 'gate' or 'choke point' increases by (n-1) fold. You can spend literally hundreds of hours trying to exterminate all the 'loopholes and exploits' and never be sure of getting them all. However, you should also take into consideration the Law of Unintended Consequences. Nothing exists on its own in a mod pack, and therefore, a change to prevent one loophole may cause another one elsewhere or may make something completely impossible to make. Multiply by the number of mods, and you begin to see how this might become a stupendous task.
However, neither Thermal Expansion nor EnderIO are particularly difficult to automate once you have achieved a certain tier level. Thermal Dynamics works hand-in-hand with Thermal Expansion to provide relatively early movement of materials with a very clever system of piping and servos/retrievers/filters that can be used to create a quite intelligent sorting system relatively early on. Likewise, EnderIO has the ability to filter and sort their ducts to provide similar functionality, and even has a new device you can hook up to have a more efficient access to everything that is somewhat reminiscent of AE's interface system.
Storage and sorting is another topic I'd like to broach here since I've touched on the subject. Some feel that easy automation and storage handling is a 'crutch', or at least that removing it can make a pack more 'difficult'. I don't happen to agree with that line of topic. It does make things more tedious, but it isn't going to increase the difficulty one iota if I have to spend ten minutes trying to find my whatzit or not. This is where a lot of what I would consider examples of 'bad balance decisions' are made. Access to materials you already have should not be considered a balance point, in my opinion. Mods like Storage Drawers make things more convenient, but not necessarily easier. In fact, I'd call Storage Drawers out as an amazingly good example of balanced storage. Each block of space has limited capacity. So you're going to end up with a wall of drawers. However, automation, once you get around to it, is as easy as a single controller. It is elegant and simple and a storage system that never becomes obsolete. Instead, your later storage solutions are built upon it as a foundation, and the controller's functionality lets you do that. With a single storage bus, you can hook up all of your drawers to your ME Network. So all those hours you spent on your drawer system will never become obsolete or 'wasted'. Instead, it is built upon.
That's another point I'd like to really address, by the way. Obsolescent technology, making things that then become no longer necessary. It really cheezes me off if I absolutely KNOW that something I am making now is going to be rendered completely useless going forward. Which is why I'd like to point out Thermal Dynamics as a prime example of how to do progression 'right'. I start off making a basic servo. That basic servo might eventually be upgraded, but there's ALWAYS uses for even basic servos where throughput isn't a really issue. It will not always be state-of-the-art, but it will always be functional.
JABBA, on the other hand, much as it pains me to admit, is starting to feel like this. A barrel wall looks really impressive, but automating it is a copper-plated pain in the posterior. Either you're going to need to do a Super-Soaryn-Drive of storage buses, or you're going to need to dump the contents into something less aesthetically pleasing just to be able to automate it. In the early game, JABBA Barrels are a great place to store cobble, dirt, and all the other byproducts of your branch-mining for resources. However, as your system grows and becomes more complex, the barrels become less and less useful, and eventually become out-moded. I know the mod author of Storage Drawers did not intend to replace JABBA, and I know he said that his mod can work with JABBA, however in my experience, I would have to actually disagree. Granted, drawers have less ultimate storage capacity, before or after upgrades, than JABBA barrels, however the level of automation permitted more than offsets this. I can't think of any scenario where I would prefer to use a JABBA barrel to a Drawer. The original Barrels came from a mod called Factorization, and were intended to be used with Routers from the same mod, which did pretty much a very similar thing to what the Drawer Controller does: a single point of interface for a bank of storage. The Router also had uses in automation as it could also be hooked up to a bank of machines, so it did have additional functionality, but the pair of Barrels and Router was quite powerful. When JABBA came out, it was just replacing barrels, and the router was left to the wayside, with automation being shouldered entirely by other mods. Granted it can be automated in other ways, using conduits or itemducts to pipe items into the system, but you have no real way to automate the retrieving of things on demand from your barrels once they are stored.