Why so much more effort put in to Championship Riven?

Why didn't the same effort go in to the re-release of the limited skins from before? This is exactly the solution that myself and many others suggested when you first said you wanted to re-release all of the original harrowing, world cup, olympic etc skins: An ever so slight variant to the skin model IN GAME. Some of those skins were even more rare and more sought after than this skin so why does it get special treatment? Would you even consider putting some effort into all the other vintage skins even if it was a sweeping, one-size-fits-all particle effect? I'd be satisfied with that.