Where and since when did it replace iptables? If you mean Debilan and Ubuntu, well, those were always "the new kids on the block" showing off with the latest and greatest, soon competing with Redmond in feature richness and ease of use (my opinion).
I wouldn't compare OpenWrt with those distros, just no sense at all.
Don't see any hype but a rush decision and I was wondering myself already 1 year ago why OpenWrt enforced this unfinished mess in at that time some release candidate - see:
But then again, I closed this thread myself and am tired of arguing objectively with subjectively minded folks on subjective impressions and beliefs. I was originally addressing the devs with a simple question/request.