Changing a good and established logo to an even better, universally loved logo would be great.

So far I don't see anything which is better that the current logo, though. Those might be fine logos for other projects, but none of the variants offered does a better job of saying "Firefox the browser" than what we have now.

Well, please keep iterating; finding a great logo takes creating a huge lot of variants that don't make it, and a lot of time.