Bungies best work is behind them. They've lost a lot of their best talent and I don't see them as a worth while investment. MS invested in small to mid size studios who I believe will produce better work.
I hate to say this but really Bungie has not produced anything groundbreaking since Halo 2
At that time there were in their own class but the Destiny concept, while a good idea, mostly failed to live up to the hype
Destiny was supposed to be the next "big thing"
Instead we got an ok but so, so flawed experience
- Scaled back gameplay from Halo (vehicles etc are way toned down). No space combat, nothing really new
- No real open world. Just static Halo style levels that you replay and replay ("you see that mountain - you can go there" - yeah right). Loading screens everywhere
- MMO-trappings all over the place to encourage grind, grind, grind
- Even WORSE story and lore than Halo
- Way worse PVP than Halo
I dont see why MS would be interested to get them back? I suppose for Destiny but it would cost more than it was worth probably..