The premise of taking heroes and changing completely their settings or the route of their lives is something amazing as an ideas, although not so original my the concept of Multiverse present not only on Marvel but DC too to be able to justify and manipulate their own order of comics (and later movies as a separate universe) that had too many events not in synchronic order or not in order with the rest of the comics at all.
How he series manages this is by a mixture of CG animations that blends the natural comic style, with sometimes impressive results. But as always it depends on the base of the story told - some are really cheesy others shows great potential and introduces even new heroes unknown in other medical from Marvel.
What If...? takes a great premise that depends on how it is tol, but as a whole the whole concept deserve a 8.0 out of 10.0 / B score by its authenticity and boldness to translate the concept from other medias into animated series.
