Every team has its drafts busts and booms as well as the same with Free Agents. There are advantages and disadvantages to both.
Drafted/undrafted players typically cost the team less on that first contract, which should provide the team with enough cap space to spend on their more proven vets. Downside is, they are for the most parts wildcards, hit or miss, since the only body of work you have to go off of is their college resume and the hope that they are teachable.
Free agents on the other hand have a potential tremendous upside, this being, you can get what you pay for. A FA usually has been around long enough for a team to know the players abilities in the NFL and who they really are on and off the field. So if a player fits your needs and your teams personality at the right price, logic would say he is your man. The downside of FA's is that there is no guarantees that said player will perform at the level you are grading them out at and history has proven this time and time again. The other downside is the cost. Desperate teams may bid that players value up way higher then it should be. This is the part that I think keeps TT out of FA and rightly so. Every year during the FA period, I picture a big poker game going on, plenty of "players" at the table....and there is TT off in a corner, wondering if he should sit in and play a hand.
TT is confident in his (and staffs) ability to scout college talent, maybe at times a bit too confident? I think most of us are in agreement that he doesn't dabble in FA enough, especially this year with some major holes not being addressed (ILB/TE). I get his sense of pride in the draft and develop philosophy, but I think its time he loosens the bank roll up each year and puts a few more proven vets on the field, not only for their skills and experience but for their veteran leadership. Said this many times, but I wonder where our defense would be today if Charles Woodson was still on it.