Does Time alignment and Phase coherency make for a better loudspeaker?

It all depends on how the designer achieves T/P coherency. 

You cannot achieve T/P coherency with room treatments. 

Past attempts at DSP were abysmal failures, but perhaps significant gains have been made in the past few years. Funny I still dont consider DSP a viable option which is probably not wise. Just dont like the idea of DSP at a fundamental level. 

Most of Thiel's speakers have demonstrated to me how a single aspect which I think is incorrect can sour the entire speaker and the listening experience. I could never get past the aggressive/forward quality of the treble. To me JT efforts to achieve time/phase alightment did so at tremendous expense. Check out the complexity of many of his crossover designs.