I agree that Watkins can recover from injury, like you pointed out with Jones, Bryant, and Edelman. It's about probability.
Matthews, while less talented, is more likely to be available to play given both of their injury histories.
Watkins might be entering his prime. He might not. Same for Matthews.
I get your point regarding our passing game and scheme fit, but my point was that, Watkins or no Watkins, Dennison's play-calling and Taylor's ability at QB are going to be relatively the same.
It boils down to a boom-or-bust argument I think. Watkins gives you the potential for a top 10 WR, but the injury and availability concerns loom. Matthews is less talented, but he's consistent and plays more often. I like the safer bet, that's all, but I do understand wanting to take that chance at the same time.
It was mentioned somewhere above, but I would think the money aspect of the whole argument has to favor Matthews.