One can only play with the hand he's dealt, and while Chelsea's squad is better than Arsenal's, it's not much better than Tottenham's.
Strikers - a wash, this one. Ade is useless but Defoe has scored some really important goals, Torres a few more than he's given credit for and Ba hasn't had a really large impact - certainly not the type you'd hope for with a new striker brought in mid-season.
Midfield - Again, not sure you can call it either way. Bale is brilliant, which gives a huge advantage to Spurs, while Dempsey, Sigs and Holtby haven't lit the world on fire, they've been decent. The same could be said of Ramires, Lampard and Moses. Marin has been non-existent. Having both Mata and Hazard would naturally make Chelsea the leaders here, but, Bale. Lennon's also been really important for Tottenham, and Dembele and Huddlestone as well have been used to good effect.
Defense and goalkeepers - Chelsea has a very respectable defense without any earth-shattering talent. John Terry used to be that, but he's now just "very good." Both teams have a large contribution of goals from their defenders. However I'm calling advantage Chelsea here because of Cech, who is in my opinion the best goalkeeper in the PL for several years running, and an overall leg-up in talent with Ivanovic and Ashley Cole.
Anyway, the point is that Chelsea don't really have a team that should be waltzing into CL qualification.
They're definitely, absolutely a better squad than Arsenal, but then you have Wenger, which changes things completely.