I suspect that Roger's improved success during the indoor season the past two years, had a lot to do with his relatively poorer results earlier in both seasons. Or to put it another way, he was more rested.
This year he's had a very busy season, and if he intends to end the year as #1 he'll end the year with something close to 90 matches played.
I think Novak will take it, but I think Federer may very well push himself hard to try and hold him off. I just don't think he'll do it.
Before I get called out on this... I'm not saying he's not awesome indoors, he clearly is. But I think his success this year might be a disadvantage at this point of the season. Possibly...
"You used to be able to disagree with people and still be friends." - Clint Eastwood