I know that revamping heroes (at least the valiants) are included in the dev roadmap for 2017. No timetable was given but I believe that it should be implemented sooner than later.
Ever since Faye was released, most new heroes have outclassed the older ones, including Valiants, rendering them obselete. We're basically nearing the point (if we're not already there) wherein you need to spend gems on every new heroes released if you want to keep up. The meta is becoming 2 of each specific new heroes in PvP (2 Faye/2 Ronan/2 Talissa).
After speaking with some friends, we basically share the common sentiment. It feels like that the older heroes that we invested in have basically become near useless because aura and skill have always been the defining value of a hero. Most of us here probably have LB'ed heroes gathering dust in the tavern, unable to find any use for them. I understand that balancing is not easy but buffing older heroes to a point that they're not useless is needed.
I'm not trying to brag or prove anything, but I'm a paying customer (not a whale though). I have almost stopped purchasing packages over the past few months because of one simple fact. If I pull the new hero, they get obselete fast and the gacha rates are literally lower compared to the past. If I pull older 5* potential heroes, they're already obselete (except for Vincent and Cybella). F2P players have it way worse as they have basically fewer pulls.
This issue has already been raised multiple times and I don't want to be called self-entitled but I believe that we deserve an official update on this at the very least.
I'm not claiming this as a fact, but my opinion is that the direction the game is heading to an irreversible point and the devs are bound to lose more loyal and potential players if this keeps up. I want to keep supporting the game but doing so has more cons than pros for F2P, non whalers, and people with little luck like me.
We need hero revamp before new heroes. I hope that they focus on this after they release the 3rd and last announced summoner.