By the 4th gen, things started to get stale. I think most of the love was gone by that point.
Instead of going forward, I recommend looking back. Try playing Pokemon Crystal on an emulator. I started recently and it's eye-opening how enjoyable it is.
Really? Which one(s) did you play?
The first 2 are actually great games, and we're especially fortunate to even have the 2nd one considering it's insane budget.
I haven't played 3, but it looked like it tried to do things differently and that didn't work.