Hard to say what he does better but what we expect from Svi is all projection at this moment.
I guess when I look at the SF position this year I consider it to be the most unproven position on the team. Even more so than the 5 now that Diallo is signed.
We all expect Svi to really improve but we also have to remember he's just now turning 18. A year to acclimate & learn the nuances of how Self wants him to play are probably big factors in his development. Also a full summer to spend on his body and individual work will also push him to be better. I still wonder about his shooting, was his low %'s a product of being overwhelmed and young or a true indication of a streaky shooter? If he's a streaky shooter than Greene is definitely the better option.
Defensively, Svi already looked capable could move his feet and really showed good pressure on his man. I didn't see him rebound much, and Greene actually was pretty good on the boards so you could consider him a better rebounder as well.
Passing and court awareness, Svi already has that going for him so advantage to the youngster.
Athletically both are downgrades from Wiggins & Oubre but those 2 guys are freak athletes so its a mute point to compare. Maybe Greene will have better movement, lateral quickness now that the injury has been dealt with. You have to think Svi will just be better at those skills because he seems more agile on his feet.
If Svi is a better shooter than last year showed, then I would probably give him the slight nod to start the season. Greene is very capable off the bench instant offense. His rebounding & shooting are his best skills at the moment.
How does Greene expand his game? Learn how to dribble and take care of the basketball. If he had a capable handle he could get his own shot more instead of relying on being set up by Mason or Graham. He's got such a great shot that he just has to learn how to fully capitalize on it. Watching Steph Curry film would be a start. Learn positional defense to limit his exposure to blow by's and out of position mistakes.
I do think Greene is very valuable to this team and I'm really holding out hope that he will improve this year..