GregTech adds a lot of gameplay. The Industrial Grinder for example offers more flexibility for ore processing. Centrifuging or electrolyzing materials into something else and building large production chains is fun. Balancing the chains with the materials you get from your quarry is a challenge in itself.
The Industrial Grinder, on its own, seems like an amazing miracle machine. Pretty much a Macerator/Pulverizer/Smashysmasher that gives you triple to quadruple output from a lot of ores and many outputs you wouldn't normally get. However, it once again only finds purpose to counteract other GregTech things. All the extra iron/copper/whatever just goes towards the increased costs GregTech puts on everything. Grinding Platinum Ore to get Iridium seems great... but without GregTech, you wouldn't have needed such ludicrous amounts of Iridium Ore in the first place.
Electrolyzer and Centrifuge just feel like prime examples of Greg-On-Greg I was talking about. You stick dusts into the machine to get... other Greg dusts, which can turn into... other Greg dusts... which turn into other Greg Dusts... or go into the Industrial Blast Furnace to make metals that only GregTech needs.
Lightning Rod and Fusion Reactor create nice bits of power... amounts that you'd only need if you're trying to run a Matter Fabricator... which is mainly for making UUM to make Iridium... to build the Lightning Rod and Fusion Reactor in the first place...
Sawmill! It gets you more planks per log! Sounds great, right? Oh, wait. It's only necessary because Greg nerfed regular logs. Yet another GregTech machine solving problems created by GregTech. But at least there's the Plate Bender, right?
Anyways, stuff like this is why I just don't understand the sentiment of "I want GregTech, but I don't want all those nerfs!" What exactly is there to want from GregTech? A bunch of Greg Machines that unlock moar Greg Machines?