with improved and additional features over the Canon original.
Admittedly, Canon missed the af assist on the st-e3, I remember even hardcore Canon enthusiasts wondering about it - maybe Canon wanted people to buy a full 600rt if they require it.
And manage to sell it at significantly lower prices.
... because they didn't have to develop, but just copy it and can just take the cream off the cake.
Group mode on pre 2012 Canon cameras
Let's wait and see if there is a catch because the guess about the problem with pre-2012 cameras is that they cannot compute 5x ettl pre-flashes in quick succession, so the Yn trigger might only work in flash M mode for some.
no (possible) hit to X-Sync for pre-2012 Canon cameras
Did they really write that - meaning you can return your Yn trigger if you see a flash bar on some pictures on older models like the 1d3?
My guess is that the probability of Yn failing with max. x-sync is about the same as Canon on older cameras, but Canon is professional enough to be on the safe side and tell people - and of course they want to sell their 2012 camera models. On newer cameras (60d, 5d2) rt seems to work @ max. x-sync just fine even with Canon.
USB-port for easy firmware updates
Well, now, Canon doesn't need that, do they :-p ? ... it's just to prevent Yn being screwed with the next Canon camera fw update.
2nd curtain sync over radio
Only feature thing missing is direct control over zoom-reflector on radio-remote-controlled speedlites.
I second that they missed these, I wished they'd added a ettl-3 including this feature on the 600rt. Obviously Canon didn't think there is a wider need for it, or they simple wanted to save r&d money.
If Canon was innovative [...] And they would be selling 430EX-RTs and EX-RT-receivers like hotcakes - even at at inflated prices.
That wouldn't be innovative because there is no innovation about a 440ex-rt or a trigger, it's just bad business to do it needlessly if people currently buy 600rt flashes instead.
Rather than fall asleep on the wheel and be overtaken by any Chinese copycat comapny (Yongnuo, Phottix, Pixel King ... ).
But they aren't overtaken, the Yn triggers is just released, and their 600rt clone isn't. Canon has ample time to do something about it: st-e4, 440ex-rt, 610ex-rt, who knows. They might be conservative, but they aren't dumb and know the market.