The goons defence has looked a lot more stable than last season, Maybe Steve Bould has worked some magic? I agree with the overall sentiment of Sfers point, I think your defence weaker is than it 'should' be, for what you expect to achieve (title challenge? top 4?)
Despite losing Song, I think your midfield is stronger, especially as Wilshire looks to be returning and Diaby 'could' be like a new signing- He looked impressive against Liverpoo, but lets not get carried away, Liverpoo were poor.
RVP will be sorely missed, you can't lose a player like that and expect no consequence, Poldi and Giroud are not of the same standard IMO, but who is?
Sfer, I'm surprised you see Gylfi, Lloris, Vertonghen and Dempsey as average, its just opinion, but I see all four as good signings that will be major parts of our first team squad. None are the calibre of Luka, but replacing him with the same quality (Moutinho) was always going to be exceedingly difficult due to budgetary restrictions and Levy having deep pockets and tiny little arms.
I had accepted we'd lose Luka, Dembele is a decent replacement IMO. I always rated VDV as a footballer, but as you rightly pointed out, he was a difficult player to involve, he completely changed the shape of our team. If Gylfi and Dempsey are seen as his replacement, then I think both will better suit our needs.
Learning to play without Luka will take time, which IMO we must give AVB.
Citeh, Chavs, Manure will be battling for 1-2-3,
Spurs, Goons, Newcastle, will battle for 4-5-6,
Liverpool, Everton for 7-8, although I see a number of teams that could quiet easily compete for 6-7-8 positions.
Injuries will always have an impact, but all teams have to contend with that and good planning and management can help to reduce the impact they (injuries) may have IMO.