I'm going to offer a few different "takes" on this question.
1.
In terms of programming this wouldn't be significantly more complex than standard bass management.
(It would simply be a matter of offering the menu options necessary to configure different filter options.)
2.
HOWEVER, that is assuming that it was included in the original planning for the firmware.
Once code has been planned, written, compiled, and tested, rearranging the routing and filter structure IS a lot of work.
(So it isn't likely to be added later as a new feature.)
3.
The simple fact is that there isn't much reason to bi-amp speakers in a home theater system (or in almost any stereo system either).
Even if your speaker offers the option there is virtually nothing to be gained by bi-amping.
One of the "benefits" of bi-amping is that, if you overload one of the amps, the resulting distortion will only affect one section of the speaker.
So, for example, if you overload the amp powering the woofer, that clipping won't be audible in the midrange and tweeter (where they would be far more noticeable).
HOWEVER, while this is useful for live concerts and nightclubs, where individual channels are quite often overdriven, it really doesn't matter much for home systems.
For one thing, in a home system, you shouldn't be driving any of the amplifiers into distortion.
For another, you don't save anything on cost by purchasing two lower-powered amplifier channels rather than one more powerful one.
(So your best option is to use a single amplifier that is powerful enough to do the job without distorting.)
Another benefit of
TRUE bi-amping is that, by using an active crossover before the power amps, you can
BYPASS the passive crossover in the speaker.
This potentially enables the amps to control the speaker drivers better by improving damping and also gives you a slight improvement in efficiency.
It also enables more specific equalization of each driver and enables you to save money by
NOT including a passive crossover in the speaker.
HOWEVER, none of this is true for normal home speakers, because in home speakers you cannot actually bypass or eliminate the passive crossover.
Some audiophiles believe that there is some audible benefit to using different types or models of amplifiers to drive the woofer and the midrange and tweeter.
While you may imagine that you would prefer "solid state punch on the woofer and tube smoothness on the midrange and tweeter"... it rarely works out that way.
What you end up with is the two parts of the speaker sounding different - resulting in an unpleasant mismatch or discontinuity in the overall sound of the speaker.
(I'm sure some few audiophiles will disagree here... and insist that they've "gotten it to work out just right"... )
And the simple fact is that most modern solid state amplifiers sound similar enough that you gain little by using two different solid state amps either.
It almost seems like it might make sense, with a lower powered AVR, to be able to "bi-amp and use both the internal amps and an additional external amp to drive your main speakers".
The catch there is that, in that situation, the external amp is usually going to be better than the internal amps, so you're better off
NOT continuing to use them.
HOWEVER, with an AVR, it would make more sense, if you have the option, to use external amps for the front channels, and continue to use the internal amps for the surrounds.
This puts the external amp on the more critical main speakers - which will benefit more from the improvement.
And, at the same time, it also enables the AVR to do a better job of running the surrounds... which both require less power and are less critical in terms of sound quality.
It's also worth mentioning that some products offer an option for "passive bi-amping" (sometimes called "vertical or horizontal bi-amping").
This simple means using two identical amplifiers or channels to drive the two halves of each speaker.
The amplifiers receive identical audio content and continue to use their internal crossovers to route the appropriate range of audio frequencies to each.
The main benefit here is a sort of watered down version of the benefits of true bi-amping... and it can be worthwhile to do
if you already have extra amplifier channels.
HOWEVER, with this option, the processor or AVR is simply giving you two copies of the same audio signal from two identical outputs for each channel that uses it.
So, if you want to do it on a device that doesn't offer the option, you can do so by simply adding a low-cost passive splitter to the outputs on each of those channels.
The bottom line is that, in a home system, there are very few situations in which you can hope for any real benefit by bi-amping.
But, if you really want to bi-amp, with normal home speakers (that have passive crossovers inside the speakers), there would be no benefit active crossovers in the processor.
I was wondering if it is possible to implement bi-amping for the mains and center channel on the MC-1: there are so many channels, and probably most of the people are using just 5-6 of them...
...this could also motivate customers to buy a more-channel power amplifier ;-)