People with better memories can correct me, but I seem to recall the same hand-wringing over depth when we put together the KG/Pierce/Allen trio.
Let's include Rondo in the main group there, to make the analogy better since we would really have a "Big 4" of IT/George/Horford/Hayward.
Then you're looking at "depth" of:
Smart/Brown/Tatum/Zizic
vs.
Perk/TA/Powe/Davis
As I recall we signed Posey and House after the Big 3 arrived, and then Cassell and PJ Brown off waivers during the season.
I think the benches above are pretty comparable. We have more uncertainty because of Tatum and Zizic but the overall talent seems greater.
So could we pick up a couple of free agents along the lines of Posey, House, Cassell and Brown? I would think that with our thin roster, the answer would be yes, as there would be vets who realize they could pursue a ring and get enough minutes to land another good contract.