Remember when we signed Salah and loads of people that hadn't seen much of him were questioning his signing, saying even if he is good he isn't what we need? This is like that all over again. Our midfield has been functional but that's about it. These two signings are a huge injection of quality. Fabinho in particular is massive for this squad because he's a dynamic #6. Much like VvD before them, Keita, Fekir and Fabinho all have crazy numbers for winning their 1v1s.
I've seen a lot of chatter about where these guys will play, some expecting Fabinho to play a box-to-box role, and people saying they expect Fekir to bolster the front line. Fabinho is versatile for sure, but he's been signed off the back of playing as a #6 and excelling there. I'm sure that's where he'll be predominantly used for us. And Fekir used to play on the wing but after losing some pace to an ACL injury has reinvented himself as an attacking midfielder.
I agree with you that GK has to be a priority now but I don't see any need to fret about this - it seems clear that we're working on Alisson.
CB isn't a real worry for me right now. VvD and Lovren have looked great together and I think the midfield we can put in front of them now is capable of making their job so much easier.
My main concern aside from a GK is depth upfront. I'm hoping we're looking for a versatile forward to cover Mane and Salah. Obviously Oxlade-Chamberlain will be doing that once he comes back but we need another. I really like the look of Traore and would certainly prefer someone of that ilk over Shaqiri.