What about if the filtering is in the low level signal? For example, my system has a Marchand active xover that uses 24db slopes with each output going to its own power amp.
It's problematic as passive line level xos (PLLXO) component values depend on the input impedance of the following component. So, put it before your amp and you can't change amps without changing the xo unless they have the same input impedance. So line level xos need to be active to avoid this issue, introducing it's own issues...
Passive speaker level xos are still the best way to do it, in general... but the issue of executing a seamless crossover in the ~(600Hz-5 kHz) or so range is difficult for even very expensive speakers to do well, obviously one big advantage of the Omega 1.5 way design. There are some big advantages to using DSP and class D amps for the woofers, including not having to build a passive high pass filter, which can be an issue as component values can be very high, so they are large and expensive. For mids and tweeters it's nice to use 1st order passive xos though, you end up with a speaker with active bass basically.
What's best really depends on your preferences though, this is in the context of preferring single driver speakers and appreciating their advantages. For someone with different preferences the best way to execute xos would be completely different and some aren't bothered by xos in the range I indicated either. So we have a large selection of speakers to choose from.