I don't think it's better than having Akon.
Akon is talented in his own right and has a wide range of skills, whether they're to your taste or not.
the main theme of a signature performance is as an MJ imitation act. The main guy from Signature is a good MJ dance imitator. Having them on the show before, during or after Mike could highlight how much slower and less able Mike is these days compared to the old days. He's 50 years old and there's no way he could compete with the speed or energy. Not trying to be harsh, it's just a fact that a fit 50 year old will not be as capable as a fit 20 or 30 something. It would be better not to have signature IMO.