c0ldk453

I agree that EE1 was arguably more balanced.  The only thing you could produce out of thin air was glowstone and obsidian.  That in and of itself was slowwww, so you needed a lot of aggregators.  You then had to make use of other mods to actually automate production of any other resource from it, which made it feel like you were really doing something.  It was incredibly similar to UU matter in that respect.  Then they basically condensed (pun intended) that down into a single block in EE2.  Which isn't to say EE2 was bad at all, mind you, just certainly easier to abuse.
As for modpacks, they tend to follow trends, and there's this whole obsession over balance these days, so I wouldn't worry too much about what they do.  If you like Project E, throw it in whichever pack you want, or just put your own together.  It's never been easier.

​That's... quite debatable.
​Personally, I preferred EE1's original system of all transmutations being done via different patterns of items in a crafting table with the philosopher's stone (and at the time it could even be automated reasonably well with the addition of Buildcraft's autocrafting tables, and it would require quite a bit more effort and thinking to set up an automatic transmutation system with it compared to something like EE2's condenser where you just shove everything into one block), but maybe that's just me.

If you wanted to make a whole pack with ProjectE as its foundation that could totally work. However, creating and maintaining a themed pack can be very time consuming and most folks just don't see the benefit of jumping through a ton of hoops just to include ProjectE when there are more clever/novel game mechanics available. To a certain degree, EE2 has just "aged out" and more mature/rich systems are what is popular.

They way that ProjectE (EE2) is OP is almost insidious when including other mods. Energy Condensers are trivially easy to bootstrap and once you have a condenser system in place it eliminates ALL other forms of resource collection, crafting, mod progression, etc. Entire tech and magic build trees are made obsolete by a trivially assembled condenser system. Yes, the condensers can be banned/blocked but the transmutation table has nearly the same issue when integrating with other mods that can make infinite amounts of "trash" items which have EMC.
ProjectE has been around for a while now and is used by a lot of folks, I'm sure. I even have a pack with it installed, but I do remove the condensors. However, it's a pack which has no easy way to make infinite items to be consumed by the transmutation table thus reducing how OP it is, and it fits the rest of the pack theme. Nearly everyone who makes modpacks is aware of ProjectE and would use it if they wanted. No one is stopping them.