People are probably going to underrate Fabbro based on the poor utilization and treatment he received last season under an incompetent coach. He's better than last season's statistics would make you think, if you are just stats-watching.
The season before, when he was Roman Josi's regular partner, Josi had an exceptional scoring season, and while Fabbro did not receive any accolades for his contribution to that, he was a steady 19-20mins a night complementary D that season, and the two seasons before, at ages 21-23 in the NHL (young ages for a regular NHL d-man!). Just his 24-year old season last year went a bit off the rails with the coach choosing to prefer a different style of play and bump Fabbro down in the rotation. We thought after the 2021-22 season that Fabbro was probably in line for something like a 4-5yrsx$4-5M contract as a steady young top-4 D. Instead, after last season's shuffle, he just got a 1x$2.5M "show me" deal while he hopefully rebuilds his reputation under a new coach.
Anyway, that's more like the backstory. Stylistically, he's a good skater in all directions, smooth, plays a pretty good heads-up style that enables transition either with skating or passing. He still tends to play more defensively and conservatively overall, however. He controls his gaps with his skating and stick, but he is not physical at all - which is probably a major reason why Hynes seemed to dislike him, as Hynes favored bigger and tougher players (who were not as good) in most situations.
I would have no problems whatsoever seeing Fabbro re-establish his spot on the Preds' 1st pair in the coming season with Josi. We already know they play very well together and that Fabbro's skating and defensive posture complements Josi's offensive tendencies very well. I don't think that will happen, however, at least not at first, as the team seems to be touting the new signing of Luke Schenn as Josi's likely starting partner. But I think they'll find over time that Schenn can't really handle those minutes, and hopefully Fabbro regains that spot. If not, well, it could be another challenging season for Fabbro to get icetime, since the Preds do have 4 guys on the right side, with Schenn, Barrie, and Carrier also all in the mix.
So it's really up in the air where Fabbro will land in the coming season and what his next contract might look like. But I think we've already seen those age 21-23 seasons of him looking like a steady top-4 player worth $4Mish. If he doesn't play enough again with the Preds next season to get that, he should probably ask for a change of scenery trade, he would be able to play more and thereby earn more playing for a different team.