No SB, it's not your negativity, just me looking at the squad.
I'm not judging 1st team or the bench - just the overall 25('ish).
Dempsey may be able to play a 'striker', but this time last year we had 3 strikers, now we have 2. We actually used 4 different strikers last year. Ditto CB, although you can compare Vertonghen to Bassong, with all due respect that isn't the point in comparing the squads. I think we used King, Daws, Kaboul, Gallas, Nelsen and Bassong last year. So although, Caulker has come through, we're lighter in that area (you could see King/Bassong/Nelsen gone and Vertonghen/Caulker in). As for MF, then I personally see Dempsey as the same as VdV (the role anyway) - so I think that the whole midfield has lost both a level of skill and depth. Maybe we're slightly better of with a 'VdV' type replacement in Dembele/Dempsey/Sigurdsson - but overall with losing Pienaar, Krancjar and Two Saints and getting back Bentley and Jenas, Hopefully Falque will shine.
Away from the overall squad, I assume Dempsey OR Sigurdsson will play the VdV role with Dembele the Modric role - I'm still not sure how AVB will work those three into the starting 11 at the same time, along with either Daffy or Ade (or both) - that's assuming always that one of Sandro/Parker/Livermore/T'Hudd will start with Bale and Lennon.