I'm a DIYer and all the speakers I currently use are DIY, so my needs are probably not as common as for many others.
My best speakers use Hypex plates, so digital inputs from preamp is a necessity. For that I use currently miniDSP SHD. I would not be trading these away easily, so anything I would acquire would need to play nicely with these. I do got multiple large (sub)woofers, that could benefit from having this kind of unit in addition to my current gear, if it had both analog low level and high level outputs.
For analog DAC+amp stage I have some strict requirements. High frequency drivers are usually very sensitive (currently 110 dB/W/m), so hf needs the best possible SNR. On some occasions I lend my system for PA purposes, so the woofers need multi-hundred Watts of clean power, so apparent solution is analog output for external amps. That's a hassle for every day life.
The digital side needs to offer a dedicated DSP channel for each speaker driver. It needs to be able to control all channels and their volume digitally. There is no signal alteration in analog domain. The preamp needs to be able to get signal from multiple sources, have adequate number of output channels, a display, (IR) remote control (some TV's use bluetooth remotes now) and analog output needs to be balanced. My TV, PC, BD-player and miniDSP all listen to one IR remote control, it's almost magical how one remote can rule them all. As a cherry on top, my current system has wake-on-signal, which contributes to ease of use, power save, component life and I couldn't live without it anymore. Trigger connector is one option for external wake-on-demand, but that also depends on the external device.
I'm constantly thinking of new designs and builds, and for that reason I need flexibility so that I can add or changes units. For example, I first built 2-way speakers, then I added powered subs. Then I upgraded the subs with passive woofers+power amps. For most of the time, the system runs with only the 2-way (TV and such) and the woofers come online on-demand by changing DSP preset. That preset changes also the crossover point. I consider this to be the perfect system for a family's living room. Now I want to add even larger subs for movie rumble. I'm not sure how I could implement this with my current gear without adding two more Hypex plates, but the fact is that only the lowest way needs much power...
For other projects, like computer speakers, I use passive crossovers and small miniamps. I could go all-active with them, you would need to compete with price. The demands are lesser than with the best system of course. Mostly a physical volume nob and USB-input.
That's what it would take to best my current system. Not easy, I spent years searching and waiting for appropriate products to emerge. For the actual DIYing I have other tools.