Channeling Spells thru your Weapon and Critical Hits

[Talya]

I mean, why should a sword of Shocking Burst stop working because it is wielded by someone with Improved Critical?

Uhhh....it doesn't? And nobody has ever suggested it did? I'm not sure i get what you're saying here. Shocking burst is always better with abilities like keen/improved crit. It's better still on weapons with extended threat ranges or improved multipliers.