This bleacher report article flaming Cecil has some familiar debate in the comments. I would disagree that the Titans are "spending money" on defense at this point, though. They are not exactly breaking the bank. I"m happy for the added depth / camp competition but it's more like a modest trickle of money.
Hopefully no one posted the link previously! Apologies if so.
As to the "it's Cecil" argument, I don't think it was one single thing. Losing Albert did, in fact, hurt a lot. Add in the slump by our aging DEs, Griffin's regression, Fisher's decision not to stock up on some depth at DB and the resulting early season debacle when there were injuries at that position, the blind dedication to Harper, and you have a lot of "non Cecil" problems. I'm sure a new D-coord did not help, at all, but I'd give him another shot.