Not really.
Its not like you NEED A TEXTURE PACK or you will die a slow and painful death.
Cool ur pants. Most likely texture pack makers will rework their textures for this.
All they have to do is make colorable areas gray and then bam
menen, it doesn't exactly work like that, i don't think.
it'll color the entire texture regardless of whether or not it's a shade of gray. if part of a texture is red and someone makes their armor blue, that part will turn purple (i think? or magenta, however color blending works.)
though when you think about it it's not that much of a problem, a similar thing happens in games like super smash brothers with multiple people as the same person.