I listened today to a snippet of Peter Crouch talking about having players at a club who demand high standards (
https://www.bbc.co.uk/sport/av/football/48199045). This made me think of the excellent Yann Kermorgant interview where he bemoaned the loss of leaders at the club.
So, the (near) necessities of a squad which will get you promoted, how many do we have/need?
Leader(s) - Every team needs someone who will do the managers job with him; someone who will make sure that the team doesn't play up or take shortcuts and hide from responsibility. Think: Roy Keane, Steven Gerrard, John Terry.

Do we have them? It seems Liam Moore might be such a leader. McShane might have been once, but his diminishing playing ability would have undermined his gravitas. Do we have any other leaders in the camp? It's just speculation, but my guess would be, no. In fact, as good a guy as Moore is, I do wonder whether he's nasty enough; teams need at least one or two players you're afraid of!
Free Kick specialist - Ian Hart (and Nicky Shorey before him) was surely worth 5 goals a season for direct, indirect and corner kicks.

Do we have this? John Swift is our best set piece taker these days, but I'm not sure he's a big step up on Baker. However, if neither of these are here next season, I'd say we're short in this department. Kelly, who could be a good taker, looks to have lost the trust of the decision makers. Set piece goals can win matches, winning matches breeds confidence and could in theory be the the difference of many places in the league table.
Runners. This is perhaps not an obvious suggestion, but I remember the way Stephen Hunt showed everyone up in the team with his work rate. If your winger can chase lost causes, then there's no reason for your midfielders and forwards to be half hearted. Managers like Klopp and Guardiola require all their players to relentlessly press the ball - it's not easy - but it's becoming part of the game.

Do we have this? Yakou Miete is a tireless runner, Jon Dadi too. Barrow, Oliveira and swift, not so much... Losing Meite would be a blow here, and would have to be replaced. Tireless and skilful is the holy grail here, but I'd honestly settle for tireless if we can only have one.
Great Keeper. This, I believe, is the most underrated position on the pitch. Emi Martinez changed everything for us at the back. He brings calm, he gives confidence and saves possibly a goal a game.

Do we have this? Well this is a problem! The very guy who has tuned us around (with of help of course from Jose, Rino, Baker, Miazga etc) is most likely, too good to come back. What we know for certain is that Walker and Jarkkola (and Mannone) are not good enough. Southwood would be a huge risk, but early signs are good. Martinez leaves a huge hole that I'm not sure many realised existed until he arrived!
X factor player - Sometimes, where you're doing everything right but can't find a goal, you need a moment of brilliance. Someone who can pick a pass out of nowhere, find a shot which threads a needle or wriggle through three tackles to break the deadlock. Dmitri Payet springs to mind, Eden Hazard, even Paul Pogba has it. In the Championship, Pablo Hernandez is able to win matches at any moment. Adel Taarabt and Anthony Knockaert both almost single handedly got their teams promoted with repeated moments of x-factorness (good word that).

Do we have this? John Swift frustrates many, but he can also do the unpredictable in a good way. Modou Barrow, like Kebe, can be unplayable on his day. Nelson Oliveira is a class player. I feel we're well stacked for technically good players (caveat: on their day!) but none are truly outstanding for this league.
No bad apples. Ok, so this is the opposite of a must-have, but worth discussing. With a squad as big as ours, it's important that everyone is doing their best. If we have players who cause trouble then they need getting rid.

Do we have this? Ironically, Norwich may have got rid of someone who was causing problems in Oliveira. But is it because he's a
leader who is unhappy that it's a problem ? Would he be an asset if he was in the right place? Hmm, it's a big question. Another irony is how the X-Factor players also happen to be the bad apples (Pogba the 'virus', the previously mentioned Taraabt, Robin Friday?!). As far as I know, there are no out-and-out bad boys amongst the squad, but apathy can be just as dangerous!
ConclusionWe're ok in most departments, but ideally we need more of all. If we lose Meite, Swift or Moore we're definitely lacking.
What else is necessary for a promotion winning side?