Looking at the mechanical group, the way bigger RD undoubtably shifts fine. But for a tri race bike with double chainrings and, say, an 11-25 cassette, I kinda prefer a small more compact RD (like currently avail with Ultegra 6800).
Is it this end of small compact RDs? If yes, this is a non-trivial negative for race bikes.
I would want to see them side by side before deciding. One nice thing is the ‘long’ arm of the 6800 was pretty notorious for not playing well with bigger tires on gravel/cyclocross bikes. There are constant thread mentions (on related forums) about the arms rubbing tires when in the large ring. That clearly doesn’t apply for most slowtwitch type bikes, but something positive to note.