Heiki at this point in time is a second fiddle driver, in no way is Hamilton restricting his progress. I would actually see his partnership with hamilton as one which forces him to push himself.
He is a good driver and has a win, but i would like to see more support from him in the races. He was not very supportive last year, especially in brazil, it would be nice if he made a Mclaren WCC a reality. But all in all i must say i like what he did in china, he was in the fray and running well against the ferraris. It was nice to see him and Lewis finishing up the last few laps together. Thats the kind of support i want to see. Hamilton didnt even try to pressure him for 1 point either so that's a good indication of the kind of chemistry on the team.
I wouldn't say he out drove Hamilton, but he was clearly having a much better day.
About the pit stops, maybe it could be related to tire wear. A little extra weight is also good in slow speed turns in the rain also. I don't see it as anything relating to lewis.
Heiki is treated well, he does not complain, and i don't think the team is denying him anything.