I don't think the lack of depth is that big of a problem, in defence we are doing well, Ivanovic, Cahill, Terry and Luiz are a great group of centre backs. Cole and Bertrand (who was excellent tonight) are a solid left back pairing, Azpilicueta (who's had a great first season and been a pleasant surprise) has taken over from Ivanovic.
Mata, Oscar, Hazard, Benayoun, Marin and Moses is more than enough, numbers wise, for the attacking midfield/wide positions. Torres and Ba is working out ok, they seem to play one game then rest whilst the other comes in.
The midfield depth is certainly an issue, Mikel, Lampard and Ramires to fill two positions every game just isn't enough. I agree Essien probably shouldn't of gone out on loan, that was a strange one.
De Bruyne wouldn't of got much playing time, even with all the games we have to play, he's doing very well in Germany so sending him on loan looks like being a great decision. Same for Chalobah and all the centre backs we have, he wouldn't of played, but the experience at Watford has been very valuable. As for McEachran, I think he just got hyped up because of the type of player he is (one of those little Barcelona types), the problem is, he just isn't very good at it
The best players in that position make the game look so easy, the likes of Xavi, Iniesta, Fabregas, Pirlo etc.. If you aren't up to the standard required to play that style, it can be very obvious as there are no hiding places. Nothing would please me more to have that kind of player come through our youth system, there could be one coming through now, but it's not McEachran.