Generally answering the following question:
Would Michael Schumacher be int the title fight if he was at MGP?
Oh man, that's quite stretching it... with 45 years of age in modern F1?
I mean in 2010, sitting with 41 years of age in a RB6? Maybe. And even back then, it would've been dependent on who would've been his teammate. If Webber, then probably yes.
But further FOUR years later? At some point, the limit is reached. I don't know maybe, but only if someone like Massa 2006 was his teammate, meaning somebody who, like Massa back in 2006, was more his fanboy than a real threat within the team.
But, for example, against Rosberg? At least, by now where everyone knows that Rosberg is also someone who is scarily ambitious as hell and willing to do almost everything to be the winner against his teammate... very difficult for Schumacher.
Remember, Rosberg was no one who has been awestruck regarding Schumacher. Even when Schumacher was demanding the lower number on his car, Rosberg didn't give a sh.t. Others maybe would've made a big fuss about it. But that episode had no impact on Rosberg.
Rosberg was Hamilton-ing Schumacher (ie "robsutly" defending) whenever the two were together on track, and I don't recall him making the most tasteful remarks off track. However, Schumacher was always better with such things, he'd shake a driver's confidence moreso than make petty nasty little remarks.
... such as telling everybody during or towards the end of the 1994 season that Hill is not championship caliber (even if it was true) and that Senna would've driven circles around him?
Or (read it somewhere) asking Brundle (when they were teammates) whether it wouldn't be too expensive for a future test driver, after Brundle showed him his expensive watch (Rolex?)...
And the demanding of the lower number come the beginning of the 2010 season was also an attempt of intimidating, sorry (no matter how often it was said that he was superstitious regarding the numbers on the car).