I've seen TONS of games have MAJOR updates and not need a wipe - the effect the changes had were clear.
It's just plain stupid to have to get rid of everything every single time a huge update happens.
Just think - there are PLENTY of ways to get around having to need wipes. You don't actually need to resort to wiping with every big update. It's called temporarily downing the server and testing it out.
Everyone does it. And it's alot more convenient than destroying all that work.
As wipes get more common, starting over and over again only to have your hard work erased is going to get boring. It's happened quite a few times and it seems like a good idea, but trust me, the novelty will wear off.
There was an accidental wipe in a certain game I played before and more then half of the players quit for good. Wiping should be considered a last resort, something to turn to when all else fails. There are other solutions that are better than this, you just need to try them.