I see that said a lot about Reborn. That you can't just go through with the same team and you have to expand beyond the usual 6, but I've gotten from the beginning to the end of E14 with the same team, and a team of 4 at that. I had 1 Pokemon up until the Mareep in Jasper, and then 2 up until I added my third and fourth just before Serra. I'm just now training my last 2 team members, because I was indecisive on who I wanted until about a week ago. I've struggled with specific battles where my team isn't a good matchup, but for the most part it's been about 5/10 difficulty which is around the range of what I can handle.
I play Reborn the same way I play the official games, because while I think encouraging people to use and appreciate Pokemon they'd never otherwise consider is awesome, I have moderate obsessive-compulsive traits and insecurities that won't be let go even if it makes my normal way of doing things unconventional.