Tbh I'm not going to go back and check but I'm pretty sure similar conversations and sentiments would've been had about this time (well, in terms of how close we are to the end of the season, anyway) last year, e.g. the teams above us can't possibly be this bad again, we have to improve massively to catch them, etc etc. Didn't happen.
Not saying that it won't happen this time around, but I don't think we're a million miles away from the teams that finished above us (at least, excluding the top 2)
Liverpool - Klopp built that team over 3-4 years, spent a couple world record transfer fees to do it (albeit funded by maximising Coutinho's value then cashing in on him). Doesn't seem likely they're going to change things up all that much.
City - Been spending stupid money for more than a decade now. Fundamentally they probably won't be too different than the last couple seasons, Ake will be an upgrade on someone like Otamendi, Torres probably won't play much at first. They're probably presuming Foden can take David Silva's place which might not be all that out there.
Man U - definitely improved the 2nd half of the season but still feels like they're massively overhyped. Have an issue with De Gea and they are still not the finished article defensively
Chelsea - as evidenced numerous times similar to Man U defensively they are a bit of a mess, have a bad situation with their 1st choice keeper, and seem intent on splashing money on attacking players instead. Also doesn't bode too well for Lampard as a tactician if he can be caught out by teams lumping the ball over the top of his backline
Leicester - started out well but faded horrendously 2nd half of the season. Personally always thought they were flat-track bullies and their results against the top teams bear this out IMO (they beat Spurs and Arsenal in the 1st half of the season when both were in shambles, otherwise got a point against Arsenal and drew twice against Chelsea)
Spurs - bit difficult to say. Jose seems to have started getting results out of them but remains to be seen how good that team actually is - CM is a mess, their record signing seems to be at loggerheads with the manager, and their star striker cannot stay healthy. They might graft their way up a bit next year but they're not going to be blow anyone away.
Arsenal - have a struggle on to keep their best player, their best CM is on loan, and defensively they still need re-jigging. As much as they had some impressive results they also managed to lose to Villa, so swings and roundabouts.
Nuno always, always stresses improvement of the team, and that focuses on the players we already have. If the core stays together then I think there is room for us to improve - not shipping the first goal was an obvious issue that we managed to fix, eventually. The most pressing thing at the moment seems to be our attacking play and not scoring enough, if we can have similar results at that end then we should pick up more points and should (!) be amongst that group again.