Can you explain what you exactly mean?
Was Willian, Hazard, Pedro, Fabregas, Azpi, Cahill etc. the downfall for the club?
I think it is very important to have tall and strong players in the starting eleven. You can have nimble, lightweight, fast players but you have to complement them, same thing from the other side. So only "strong" players is also not a good balance.
Bolt example. I would rather have Loftus cheek defend a lead than Gilmour. No matter how hard Gilmour tries the 6'2 guy will just brush him aside in a corner or whatever.