I would agree. At the moment some of the talk is about still waiting for the team to gel - VdV seemed to come in and make an impact straight away, and even though I thought Modric and him seemed to want to play similar roles, he still seemed to be a class act. I haven't seen Dempsey or Sigurdsson either link up the way he did or provide a similar goal threat - as yet.
But you can't expect to lose players of the like of Modric/VdV without it having some impact - especially when it seems that their first choice replacement couldn't be prised away from their current club.
I'm not sure though that the difference would be that noticeable if Ade was starting and playing like last season. I think that the style of Ade's play and his off ball work made it 'easier' for the supporting midfielder.