Most places, 95% perhaps, what OEI AA you chose has no consequence whatsoever. The remaining 5% it has a very clear and immediate impact, and buggering around with it can terminate you if you lose one donkey.
For that reason, I am sure we all agree that the OEI AA needs to be respected, full stop.
Now, let's say you have all donkeys burning - so you can retract your flaps at a lower altitude, right?
Consider losing your engine before you reach en-route climb speed, ie between V2+10-20 and Venr. You now have to continue acceleration or stay at whatever speed you're at, in neither case knowing where you are in respect to obstacle clearance. Or could re-deploy flaps and drop back to V2+10, but that somehow defies the purpose of the exercise...
You know that you're quite a bit above the OEI flightpath when you start retracting at eg 400 ft, but how much? Enough?? If you have a 1500 ft ADER acceleration height, you might make it up there and still be above the OEI path from 35ft at this stage - but what if it's 2000 ft? 3000?
Problem is that if you roll the flaps before you reach your obstacle clearance altitude and you lose a donkey immediately after, you have no scooby doo about where you are or will end up in relation to your OEI path.
OEMs only build the things and specify the minimum certified height they want you to retract the flaps. Consider CMF, ASE, INN, SFJ etc etc etc. - your AA is waaay above cert minimum in all these cases, so by respecting your performance needs, are you flying the aircraft contrary to how the OEM tells you how to fly it?? A careful look at the AFM will reveal correction tables for 2nd segment extended above 400/1500 ft respectively.
In other words - the OEM only builds and certifies your aircraft - you, your company and your authority must then come up with how you operate it. Suffices to say that if you roll flaps at 400 ft at either of the above mentioned places or their relatives, you clearly have had an imagination failure
You don't
need to put yourself in that (flapless) position, so why do it?
Deck angle limits need to be respected, but the old idea about the owner firing your sorry ass because you exceed 8-10 degrees? Had a very nervous owners wife out of INN on a CL30 telling me not fly out of there too steeply
flew the usual profile reaching 18 deg ANU, she afterwards said it was the best takeoff ever... They don't often notice a deck angle - but they DO notice a shoddy (ie too fast) rotation rate...
Anyone here ever actually had a pax complain about deck angle?? Would be interested to run a poll...