Just to clarify - you're talking about pre-2010 [old] vs post-2010 [new] - right? [Not the really "vintage" Chanel].
I've read posts here from people complaining about the longevity, but I havent really noticed that much difference. Both versions are fairly long lasting on me, with good silliage [I dont know about massive - but I can smell it]. The difference is in the actual smell. The whole middle part is now gone. You're basically left with the base and little else. Maybe in that sense - yeah - the old one went through more changes, so lasted longer.
Im still trying to find something to layer the new one with to get something similar to the old one. Im going to try Liu - which is most similar in the opening - it has that same kind of [ugh! - it's hard for me to describe smells in words] - but it's kind of similar and might work.