bombaywalla --phusis, i'm sorry to say but you are wrong!
There are too many other factors for a phase-coherent speaker to potentially sound like the less desirable choice compared to a speaker not being phase-coherent. I’m guessing you refer to speakers being mechanically aligned to achieve named virtue, although delay via DSP is a viable solution as well - likely better than any electrical ditto. In any case, phase-coherency alone - to my ears, at least - is far from the deciding factor.
The thought experiment could be made whether a hypothetical speaker of my liking, one not being phase coherent, would gain significantly being converted into phase-coherency. For the sake of not altering the overall design of the speaker let's just say we'd modify it accordingly via a DSP solution, bearing in mind other sonic changes that could follow in the wake of this implementation. In that case, given these are speakers I'd fancy despite of phase imperfections, I gather the phase modification (into coherency) could lead to the desirable outcome. If anything, and if proved to be a big factor, the rationale could be to seek out the overall preferred speaker principle as a phase coherent design, but as such phase coherency would only be one of many factors to achieve the desired sonic goal.
you need to go back & read a couple of really great threads (if you haven't already) &/or re-read them -
* Is DEQX a game changer?
* Sloped baffle
there is a lot of great info in these threads that will dispel a lot misconceptions you have...
A correction re. what you wrote - i'm talking about TIME-coherency (& not phase-coherency). These are 2 different things with time-coherency being the superset. A time-coherent speaker is always phase-coherent but a phase-coherent speaker is not time-coherent.
Time-coherency in a speaker is a design paradigm; it's a parameter that you trade-off in the midst of speaker design as you are thinking. Once you make up your mind to manuf a time-coherent speaker it dictates how you build that speaker. It's a decision you make at the very start.
You are talking about "mechanical alignment" - that's but one very small aspect of time-coherency in a speaker. Merely having a sloped baffle means very little (it just means that the acoustical centers of the drivers are on a vertical plane) if the rest of the speaker design doesn't take it all the way towards making that speaker time-coherent.