I think in "medium" size arenas like Marseille (or Barcelona the last two years)... almost anywhere is a "good" spot - if you actually just want to watch the skating. Nowhere is very far from the ice, and it won't be full for the practices either.If you don't care about seeing Hanyu from a good spot, you can sleep in, but chances are if you are coming to see someone in another group who skates before him in the practices... It may be very busy. ;-)
I think the rush/melee/battle is mostly between Ubers trying to get as close as possible to the object of their obsession :-D - especially seats close to where the skaters/coaches will stand when conferring... although the seats don't go right down to the rink, so there's nowhere that's very close to the ice either! :-D
I'm not the Uber/groupie type so I don't mind sitting further back... and taking my time in the mornings to have relaxed breakfast, leisurely stroll to the rink, etc... :-D