At the actual state of the game chars or classes rework is pointless to me. Finishing the campaign is very easy and you can do it with almost every comp (mix of 3* and 4* with 4*talismans).

Speaking about the future... it's hard to say now, but i see the sentinels in good shape, they provide a good amount of particular abilities in the game and i never seen this game as "you have a main char", you have 3 eddies you can use togheter and combine as you wish. So the point for me is that until the eddie-sentinels bring something you can't have in the same way from the others they are ok. As allies some sentinels are already top-tier (soulless demon, green bat, allies commander) so i don't think they need a buff.