Love is a solid player, but I'd like to see his snaps scaled back a bit. Wilfork's too. That's why I think we need another DT.
As for Gregory and Wilson... I like Wilson as a 3rd safety more than a starter. He seems more comfortable playing in that role. Maybe that's inexperience, but it could just be his skill set. Gregory is a solid starter at S, but solid means room for improvement and I think safety is a spot they could make that improvement without spending too much money or taking a guy too high in the draft.
I definitely agree with your thoughts. It is unbelievable how durable Wilfork is with the amount of snaps he plays, and it would be foolish to expect him to keep this up for the next few years. My dream scenario is John Jenkins falling down the draft boards so that we can either take him with our first rounder, or move up a bit and snag him. It would be quite similar to Vince's draft day fall, and I see some similarities between the two players.