The coh2charts so far only display how many games have been played, not winrates. GCS is confined to "balanced" maps. Had other maps been in the pool that were allies advantageous their winrates would be much higher.
1-CoH2Charts does display winrates (just filter for 1v1, arranged teams or randoms) but that doesn't translates automatically to a fact for claiming that X or Y is imba. As i said before, it shows a trend. A sign something MIGHT not be right.
With the nature of CoH (low playerbase, high amount of imba skillwise matches, assymetrical faction/maps balance) it's hard to use this values but i personally consider that between +5 is practically acceptable. Anything higher than that it MIGHT mean something is not right.
NOTE: there's a thread by Siphon X which explains it better. But you have to be naive to ignore the meta matchmaking movement of people swapping factions cause "they are now more enjoyable".
High skill level balance is what matter, so GCS is in fact more important, but you need to have some kind of perspective of how the average player is doing as well.
At the moment the trend seems to be simil.
2-About maps. Problem with matchmaking is that you can't know which map you are gonna land on nor your opponents so you can't really prepare for them. On a tournament setup, you know up to some point which faction your opponent prefers, map and what commanders you can fill for that map. EVEN if a map is slightly favour for one or either side, the overall sample shouldn't be as DRASTIC for some factions.
Kholodny and Faymonville threw "balanced" average results on previous ESL cup. Crossing has always been imba and that leaves Crossroads. Do you really thing that if we threw into the mix Semoisky, Langres, Angoville or any other map the values would vary so much?
TL;DR: just in case this smells like Axis OP allies UP. It's more of: there's smoke in the horizon. It should be a GOOD idea that the scope was bigger this time. After nerfing cheese and leaving untouched some factions, it was expectable to see this kinds of results. Which doesn't mean the patch is bad, just that it shows how some factions strenght was only on it's cheese and not "proper" gameplay.