I mean gamble in the sense that nothing is really guaranteed, you're right that risk vs. reward is extremely important. We saw that play out with Tua last year. These guys are given a ton of feedback at the end of the year, more than any other CFB team. It's ultimately up to them and their families what to do with the info and recommendations, but they won't lack the resources and feedback at UA under Saban.
Tony will rate all the draft eligible players in the spring just based off his own reviews. I seem to remember him having Waddle outside round 1. But, his ranking and actual NFL scout rankings don't always match up. I do know that he's mentioned more recently that scouts had Smith rated a half round higher (which would tell me, they had Waddle in the mid-later part of round 1). Ja'Marr Chase is WR1 with most teams, even ahead of Smith, but that can change (plus as we have seen draft after draft, boards obviously differ from team to team).