My friend who's a bolts fan said he's Marschessault-esque in the fact that he didn't get a lot of minutes with TB but could be really good given more opportunities. Said he was often scratched but played well when he got a shot.
I am also a Lightning fan and this is all accurate. Obviously had limited opportunities in Tampa, especially in the top-9, but he's more skilled than your usual 4th liner. I think he'd be at least a 3rd liner on a lot of teams. If anything he was honestly pretty snake bitten in the playoffs. Also as was pointed out he tore up the AHL.
He is sort of like Marchessault in that even when he did play, there was never much of an opportunity to fully utilize his skillset considering he was almost always playing with Paquette and Maroon. Both additional minutes and more skilled linemates could lead to a really productive season from a guy who was already pretty productive on a per 60 basis.
Idk about possession numbers and advanced metrics and all that, this is just my perspective as someone who watched him play quite a bit. I was disappointed he was leaving a team I like in Tampa, but hyped when I found out he was joining another team I like in Florida.
Bottom line is he's young, pretty skilled, and could potentially be really productive with an increased opportunity. That imo is well worth the contract they gave him.