Who says their weaker? They'll probably still finish top four again but as we saw with Arsenal for years and what we see with Tottenham, the mentality to win medals is either there or it isn't.
I won't be confident if we have a title race with City as I feel their experience in them will see them through, it's highly unlikely both City and Liverpool will be so poor to allow this to happen but I'd be mega confident if we end up in one with United.