In terms of implementation, the specifics of the particular type of aircraft is presumably a relevant factor: how to tailor AP response (the “umbrella AP” controlling all IF aircraft using AP) to unique engine response time and usable thrust relative to inertia, plus the unique drag profile at the time of the power change (for the particular aircraft in use at the time).
If a gradual throttle-up is not “tuned” appropriately for a particular aircraft, for example, one aircraft may be fine, but another might have an excessive drop in IAS before it reaches equilibrium of forces, for example.
The above is not claiming smoother power response can’t be done, it’s outlining potentially, why the issue involves some complexity (consumption of resources to implement).
The most effective UI might not be complicated in concept on the surface, by being paid for with a lot of unseen complexity “under-the-hood.” But human-factors-friendly is obviously hugely important.
I assume you mean VNAV doesn’t set altitude in the irl ALT mode. But VNAV obviously sets altitude internally to its own independent function (the profile):
Again, the above relating how the independence of function you describe adds to the overall functionality: the independent modes provide more powerful combined functionality by each being independent of the other.
Again, your example of the power of independent mode functionality:
But somewhere you have altitudes entered before the time of transferring each such goal to the AP, so that you don’t have to be scrolling through numbers each time you need the next alt?
Yeah, I think I misunderstood someone else’s point on that recently.
Again, it would be very cool to see that.
A given aircraft at a given load, density altitude, power setting, and IAS, has a unique pitch for a given VS (in unaccelerated flight).
So, your point is I presume, in spite of the above, for any aircraft as long as IAS shows any hint of deceleration, the system feedback is: keep lowering pitch until reaching the VS necessary to halt the IAS decrease*, and then eventually (at some altitude) you arrive at the pitch for VS = 0? Even if thrust output changes with altitude, so aircraft dependence should, one presumes, be little to none? (Am I missing something I might think of later?)
Though there is still the question of how the above might affect “gameplay” across a wide user group.
*edit: I don’t know with complete certainty there wouldn’t be some comparative rate of response issue in the IAS’s feedback for how different aircraft are modelled (a lot of things seem pretty simple until you test the implementation).