While I'm intrigued by Wiseman, I don't think it would be wise to get him.
Sure in theory, a top prospect a few years ago, who has had a lot of set backs, but has a huge upside, is inexpensive to obtain, fills a position of need now (backup C), and can be Horford's replacement in the future, with a timeline that aligns with Tatum's and Brown's prime, seems like a no-brainer move.
But if he can't find time on the Warriors, a team also competing for a championship now like the C's and who doesn't have anybody over 6'9" on the team, and he still can't get minutes, I don't know how he'd get any time here.
Then there's his salary. It's not my money, but $10m in salary for a project is a lot. especially when you add in the luxury tax hit. People have been speculating that the team can afford Grant next year because of the bargain contracts for Rob and Al. While Wiseman certainly has a higher ceiling than Grant, the Warriors just chose an 8th man over him.
He'd have the same problems here as he was having on the Warriors. Wouldn't help the team win now so wouldn't get the minutes to help his development, and costs the team too much (from a salary/tax perspective).