[arch-general] multiarch support like debian, pro and cons?

I wrote my idea first on the irc, but i think here is a better place. The idea is to give up multiarch repo and make pacman and archlinux capable for real multiarch support That means u could install a 32bit package from the normal repos core, extra, community usw and not from multilib repo in 64bit arch. (example: pacman -S firefox:i386) And that means package maintainer don´t have to maintain two 32bit packages, plus all 32bit package where available ob 64bit. What are u guys thinking, about that ideas. What where the pro and cons, that i don´t see. Greetings, Ranomier