Saying that, Isner's rise could be down to the weakness of the field outside the top four. The bottom half of the top ten is basically open season for anyone in the top 30 prepared to get their act together. Look at the gatecrashers in the last year or so - Melzer, Almagro, Fish, Tipsarevic and so on. These are top-30 guys.
I disagree. Last year it was quite weak, with even Troicki getting there or thereabouts, but it's much stronger this year. Tsonga, Berdych and Ferrer are in their own little league, but the likes of Fish, Tipsarevic and Del Potro have all been very consistent over the last year and are all capable of beating the top guys. Tipsarevic and Fish have improved in leaps and bounds in the last year.
Isner's wins over Djokovic and Federer suggest otherwise as well!
I think the top 10 field is a lot stronger than this time last year.
As for RG, I think you could be right on that. Don't think he will win it like, but could certainly provide a shock or two after his recent results.