...Why do people feel the need to attack opposing opinions?
I think your opinion about Gen 4 having better designs than Gen III is the complete inverse of the truth, and that's just my opinion. Both are irrelevant to Rai's point that he doesn't want his past favorite Pokemon to be given a poor evolution. I can understand Rai's fear of having an old favorite given an evolution that "ruins" (in that person's mind, of course) it's look and flavor.
My main problem with this is you can still like the old Pokemon. They aren't going anywhere, and they aren't ANY less viable than before. Electabuzz gaining an evolution didn't make it any less viable, or change its design whatsoever. However, some people love Electivire, and it contributed something to competitive Pokemon. There's no rational reason to be against an evolution.