?? I looked up the game because I hadn't heard of it, the graphics in Wakfu are amazing, nice and clean, easily 2-3 times the resolution of the UO Enhanced Client, incredibly detailed, very little repetition (though shockingly similar to NISs art style, a rival company that makes other tactical rpgs....hmmm). The NES had an effective max resolution of 256x240, there's individual tiles in those screenshots with more image data than that.... Not terribly fitting of UO of course but comeon guys, give credit where credit is due, the games graphics are great.
To the OP, the reason is because EA has to make a new 3d client to replace the old failed 3d client every 5 years that only 5% of the population will ever use due to being perpetual beta. I wish instead they would just sit down, hire a artist, and do a 6 month touchup of the 2d graphics, triple the resolution of the ingame 2d art (not terribly hard to do, a little time consuming though, i forget the link but a few players here posted examples years back of what UO's art could look like if it was simply touched up instead of replaced, and it was amazing) and allow the CC to use higher resolutions (again, not that hard to do, actually a fairly simple fix)
And while they're at it, revert the worldmap changes they did for KR, it made a lot of areas look horrible in the CC.