It's a completely viable strategy, and was in the previous version of this game as well. There aren't many top level FB/press teams in D1, and I'd say that's the only kind of team that really needs to be concerned about a walk-on or two. At the same time, if you concentrate only on top level talent for your rotation, you are sacrificing depth, and some flexibility in terms of dealing with unexpected early entries, or having a poor recruiting session. There's a trade off, and there are consequences for both strategies, as it should be.