Typically, in a good safety class, you get about 8 safeties (FS and SS) taken in the top 3 rounds. In a great year like this, it could be more (or indeed less if the abundance of good players means teams don't rush to fill a need in the early rounds).
Hooker, Adams, Peppers, Baker, Melifonwu, Williams are probably locks for the top 75 picks. Plus King is being looked at as a possible safety or hybrid and you have to now factor in some LB/S hybrids like Peppers who might be factors (Elijah Lee?). To make 8 players, you have Maye, Jackson, Evans, Josh Jones and any one of a few guys who will rise post-combine/workouts to fill that out. Xavier Woods is a contender to do that, imo. In that sense, Jackson in the 3rd isn't that unlikely to me. If he goes higher, it'll be because one of the other guys probably dropped into that range.
He's not a Miami safety, to my eyes. Great reader of the game, quick, takes good angles, but he's doesn't make his presence felt they way you would expect an All-American safety to do. It's patient and efficient, his style, with great nous and good technique, but there's an economy of effort in there that I don't think is what our coaches are looking for. Not wild about his coverage at times either - lets receivers get separation too easily. I think more the Humphrey model of being a missile and a pain in the a$$ is what Gase wants, but in a safety. Budda Baker, Jamal Adams, Malik Hooker, Xavier Woods and others have that mentality of not leaving it for someone else to do if they can reach the play. They take the killshot. I love that. Jackson is a bit too patient for my taste.