I beat the Elite 4 and Champion a while ago, and I'm going to post some thoughts.
I didn't have much trouble with the Elite 4 otherwise than Lance, but he has 2 very powerful dragons, so it's expected.
By the way, although he does have Dragonairs in Gen 1/Gen 3, the Zweilous and Fraxure seem a bit off in the final Elite 4 member's team. Thing is, Lance has been characterized by having Pokemon that weren't Dragons, outside of rematch battles: He's often seen using Aerodactyl and Gyarados, and has Charizard in his Johto team. I think the not-fully evolved dragons should be replaced with Scrafty or Archeops or something, I dunno. His entire team seems pretty weak to ice, anyways.
The Kanto and Unova Rush seem very fair: 3 Fully trained mons per opponent vs. 6 non trained mons is ok for a challenge. I really am liking it. It's implemented well, and the new items are awesome.
I only found one bug: After losing to Bruno in Kanto Rush, I ended up with a Bag full of ??????? things. I suspect that it was caused by checking for more heals when I had ran out, but whatever. Don't worry, I restarted without saving afterwards, so my items are safe.
This hack is very good. It managed to live up to hype. Maybe not the Yet Another Fire Red hack levels, which is one of my favorite hacks of all time, but it comes really darn close. Nice work.