My 03 has the same thing you're talking about but I'm also running a tapered bearing carrier in mine with an aftermarket swingarm, as well as a Lonestar axle. There's so much contact area there that a little bit of play will take a heck of a long time to wear out those splines!!

As far as replacing bearings, it is not a big deal. You just need a pair of bearings and some new seals to put in. Just drive the old ones out with a brass drift punch and put the new ones in the same way. Just be careful to hit the outer bearing race rather than the inner one when you're putting the new bearings in... otherwise you could shorten the life of your new bearings.

Hope this helps.