aterpster -
If the aircraft is at V2 (or slightly greater) Vmca is not a factor with an engine failure
If the speed schedule is V2min limited (generally at minimum weight, say a short ferry flight), then Vmca might not be too far below V2. Mishandle the failure by banking the wrong way and it might get interesting - depends on CG etc on the day but not something to be dismissed as you appear to be doing I suggest.
If the takeoff flight path is obstacle limited then not increasing the power after an engine failure will limit payload
In general that is not so as the reduced thrust takeoff has already considered the obstacle profile (and all the usual things which go into determining the RTOW).
Also, if you have commenced the takeoff, which appears to be a prerequisite to having an engine failure consideration, then how can pushing up the throttle increase your payload at the time you have the failure during the takeoff ? .. or am I missing something obvious to you but mystifying to me ?
perhaps cause the takeoff flight path to fall below minimum regulatory requirements
Likewise, not so as ALL the regulatory requirements have been considered in determining the reduced thrust RTOW data.
I think that we need to call your bluff and ask you to cite some authoritative data to support your claims ?
Now, mutt and I are experienced ops engineers and I don't think we have knowledge of such generic problems ....