It seemes to me, that if all else was equal, but one speaker was not time and phase alligned, and the other was, the one that was would sound better.
And I even have a bit of pretty strong evidence that this is the case.
The late Jeff Bagby, well respected speaker designer (professionally, and among DIY’s), designed 2 versions of the same speaker using the great SB Acoustics Sartori drivers.
The Kairos, which is time and phase alligned, and the Adelphos for those that are intimidated by building a cabinet with a slaneted baffle. There are also crossover differences, too, in order to compemsate for the flat vs slanted baffle.
Here are the kits and write ups:
Kairos
Adelphos
My friend and I built a set of both speakers, and compared. No question, the Kairos imaged better and created a bigger soundstage than the Adelphos. Other than those parameters, other aspects sounded, to our ears, identical.
And let me add, as with most well designed DIY speakers, the end result with both the Kairos and the Adelphos, are speakers that end up sounding as good as commercially available speakers at several times the money spent.