The only thing against Sol for FP5 that I see (besides not being a mainstream character) is that the previous DLC fighter was Terry. I don't think it's a bad thing, because we had Joker and Hero in a row, and both are completely different in terms of moveset and aesthetics. Same for Terry and Sol, but maybe Sakurai would prefer Sol to be a post-pass character, if he's even considered for DLC, of course.
One Youtuber that I've subscribed to, FeliciaFan, put out a moveset for Sol Badguy. His movesets are quite detailed, so it could help to show how Sol could work in Smash to people who aren't familiar with Guilty Gear.
I share the video yesterday in the newcomer speculation thread. I found the video in my suggestions on Youtube.
As I said in the other thread I think the video is very well made and represents GG in a great way but at the same time, the moveset gave me the impressions that maybe it would be a little more complicated that it should be.
His final smash should definitely get the Joker treatment. If Sol kills with it "DESTROYED" appear at the screen and Sol says something after that. But even if instant kills are precisely that in GG I don't know if it would be correct to maintain that in Smash. I mean, dying at 0% because your opponent hit you with the final smash would be a bit hilarious xD
Which Guilty Gear game do you suggest me to start with?
Accent Core is a great game. I'm not a GG expert but I would say GG Xrd Revelator is a bit more friendly beginner. There are cool tutorials in Accent Core but the ones in Revelator are very cool and well designed for new players.
You have story mode and arcade mode in Accent Core and Xrd, and some more content for singleplayer. I think Xrd is maybe a bit better for a newcomer because I think it's a bit easier in terms of difficulty. Not talking about mechanics and gameplay, I'm talking about difficulty level and all that. I started with GG Xrd Rev 2 and I felt that the CPU it's not that punishing like in Accent Core.
Maybe I'm wrong about that, of course, but that was my impression.
In terms of story Accent Core is before Xrd, I don't know if you care about that. One of the things why I was interested in Guilty Gear was the strong story mode content. Revelator story is like an anime movie, 3-4 hours if I remember correctly.