When you ask about point sources, what are you referring to? Full range drivers? Concentric drivers? Coaxials? a tweeter and mid placed very close together?
In any case, point sources can work. It depends what you are looking for. Out of the above choices, the best compromise would probably be the concentric drivers. It essentially a woofer with a tweeter placed at the base of the cone so the VC of the two drivers are the same distance from the listener resulting in the best time aligment. Coaxials are much cheaper but less dynamic. Full range speakers must be small diameter speakers to produce any kind of decent off axis response but there are some full range speakers that are among the best speakers in the world. The Manger is one of these and there are some Lowther zealots who swear by them. Another good brand of full range drivers is Jordan but they tend to get a little harsh in the last half octave of their response. The advantage to a full range unit is the ability to go without a crossover and therefore eliminate electronics between the source and speakers resulting in better phase control.
http://www.cabasse.com/hp/tc21/etc21.htm Check the Cabasse TC21 for what is probably the best concentric driver in existence and perhaps the best driver in any class.
