Is it an exploit? yes, is it bad? well, that depends.
I play SSP, and I used it to get some blaze rods early game, it also meant that I didn't have to hunt blazes. But here's the thing
Nobody is forcing you to use this.
Don't like it? don't use it?
I often used the iron-> ender pearl feature of EE as well, but right now, I have access to the end, and in the process of making my Tier 5 Enderman Soul Shard, I ended up with a heap of pearls (I also had looting on my soul stealer sword). But early game, it was much easier for me to just wear the cost of the extra iron to make the few ender pearls that I needed rather than having to hunt for them.
I've seen a worse exploit than what's listed above.
Kill a skeleton, and get the bones. Then macerate or pulverise that to get as much bone meal as possible. Then with the forge lexicon, you can turn this into a bucket of white dye. All seem OK right now? OK, so then use that bucket of white dye in a recipe, and what do you get back? why an empty bucket of course, which you can smelt in an alloy furnace to get 3 iron. Even with vanilla, you get 2 bone meal per bone, with TE you get 6 bone meal, and with IC2 you get 5. So with TE and RP2, you can get 18 iron out of a single bone. It's not hard to build a mob grinder if you have a void age, or if you have access to skeleton spawners it's pretty easy to grind them that way. But again.
Nobody if forcing you to use this.
I play for fun, I play for the enjoyment of building things and getting lots of stuff in game, some of it I get legitimately, some of it I get via an exploit, but that's my decision, if the EE Author decides to nerf the Blaze Powder -> Blaze Rod then I'll live with it. If they decide to remove Iron->Ender Pearl, then I'll live with it.
You can argue till the cows come home that EE is an exploit full stop, e.g. dirt is always plentiful, sand, not so much. But sand can be made from dirt via a minum stone, you can make clay in a similar way (it's just a bit more expensive). This means that you may not have to find a desert/beach/swamp etc to find clay once you have a minum stone. I think that's a good thing. Long term, it's not feasible once you need a lot of sand, but I can make sand by pulverising cobblestone, so you can just as easily argue that it's an exploit as well (hell, I've got 2 extra dimensional chests full of cobblestone).
I did read somewhere that the problem is that very few people play with just one mod. Most mods are written with vanilla in mind, not other mods. Once you start putting multiple mods together, especially ones that give different amounts from raw materials, you generate a possibility of an exploit.
