I don’t have a personal problem with Wikimania as a name, but there are some liabilities:
1. It isn’t terribly descriptive of the event we hold, as it is a pretty standard conference with session proposals, meetings and training. Occasionally, it will go “mania” with some more innovative and offbeat ideas.
2. On first glance, the name isn’t very professional sounding. So it may be hard to convince one’s boss or academic head to fund travel or time off to attend the premier conference for the Wikimedia community.
In the US, we’ve gone with “Wikiconference” as the name for the national/regional gathering.
-Andrew