I don't see how colonial costumes are any more "dated" in 2012 than they were in 1982. It's not like they were the current style back then, so changing from the current costumes doesn't really address the issue of World Showcase being dated. World Showcase is dated, where it is dated, not because of costumes, but because Disney hasn't updated technology from the 1980s. It's dated not back to thematic periods portrayed in the costumes, it's dated to the 1980s. Addressing costumes doesn't fix that in the least.
If anything, modernizing the costumes only creates more problems, because "modern" is a moving target, where as colonial is pretty well fixed in time. Unless Disney constantly updates the modern costumes (want to take bets on that happening?), the new costumes will be dated in a few years.
The "Disney isn't a museum" argument is treated as some sort of panacea by some on here to justify any change. Well, with regard to World Showcase, in some ways, it SHOULD be a museum. This is reflected everywhere in World Showcase from the architecture, to the cuisine, to the costumes. This is for good reason--the most culturally interesting aspects of these countries are, to some degree, time capsules of earlier times. I certainly wouldn't want to walk into Japan and see a giant Sony animated billboard and a McDonald's restaurant...
I don't need to "see the costumes before passing judgment" in that regard. The new costumes could look awesome, but no matter how awesome they are, the fact remains that they are not a legitimate fix to any complaints that World Showcase is dated.
Beyond all of that, I really hope Lonnie doesn't lose his job because of all this. He's an awesome Cast Member.