Theoretically we've brought in better players, but we don't know that yet.
I'd say Burgess is an upgrade on Darling, but that doesn't really help us in an attacking sense (and actually may be a downgrade in terms of threat at attacking set-pieces, although the Forest game showed what Burgess could bring in that sense).
Galbraith is an upgrade on Allen in that he's regularly available to play, not sure he's a better player than Joe though. Don't think either of Yalcouye or Stamenic have looked better than O'Brien.
I'd say Inoussa is a big improvement on Eom.
The likes of Wales, Idah, Casey, Benson, and Samuels-Smith haven't played enough to declare them better than what we had last season.
We need to get better but as Andrew said above, it's a dangerous idea to think we've got this amazing team being held back by the manager. It may be the case, but fans have thought that many times and been proven wrong.