I don't see how this "critical hit" system is an improvement. Rolling damage dice is FUN. Rolling more dice on a special occasion is even more fun. Now, in 4e, a critical hit means you roll no damage dice at all (or fewer). It seems like a real step backward in fun, to me.
No confirmation roll? Again, less fun. That moment between rolling the critical threat and rolling the confirmation die is one of the most exciting, most tense moments in D&D. When that confirmation roll succeeds, it really feels special. High-fives all around, hooting and hollering, etc. If you fail, well, you still do normal damage! This 4e system is...anticlimactic. A 20! Okay, my turn's over, next!
Finally, did critical hits really need fixing? Really?
The new system won't be "broken" or anything. It'll be faster, yes, and simpler, but not better.