I myself actually prefer the route the show took, i.e. following Bruce and Jim from the moment Thomas and Martha were murdered, without any major flash forward. Yes the show would definitely be better if they were ensured 7 seasons from the start, so it probably would have benefited if they had had cast a 17-year-old actor to play 13-year-old Bruce, so they could have afforded both minor flash forward and keeping the original cast, but for me David Mazouz's portrayal of Bruce outweight all of that benefit.
Anyway despite this being my top 5 shows in a few recent years, it still has lots of missed opportunities, and I find it appropriate for it to end here. Of course what works for me doesn't work for many, and for those who follow Gotham but don't like the route it took, I hope you still enjoy some aspects of the show throughout the years; otherwise if you hate all of it then it's better to just watch and comment the finale (like some members in the 5x12 thread) rather than spending time watching something you don't enjoy and hoping it would one day get better.