The fact of the matter comes down to this, we won't effectively be able to play any 4 at the back formation because we only have two proper fullbacks and our wide talent is lacking as well, sure you can say Mata plays there but I've never been a fan, Di Maria looks better more centrally.
I'm not saying January signings are easy, but City and Chelsea have stengthened paying big money to get someone who will improve them and we can make all the excuses in the world, but it won't mean a thing if we don't make top 4. Also I think we're clutching at straws a bit saying we wouldn't take Cuadrado, he'd be brilliant as a utility player for us covering a range of wide positions with much better quality than the options we have now (bar perhaps Di Maria, but he hasn't been great and I prefer him more centrally). Not to mention the lack of players we have there, even as a wingback in 3-5-2 etc. He'd give us options we don't effectively have.
A lot of our weaknesses have not just come about, they've been around since last summer (and before) but weren't addressed.
We are unbalanced, lacking quality to get any real consistent performances due to the areas of formations and the players we have in certain positons just aren't effective enough, or we lack any depth if they get injured, we revert straight back to 3 at the back again.