hmmmm, interesting thread going on here.
i wouldn't necessarily say that there will be no "thump" in the kick drum or good low end. remember low frequencies are omnidirectional and sound eminates spherically from it's source. If his microphones are 3 feet from the stacks 10' above the subs I'd say he'll still be getting a decent low end, but nothing outstabnding that's for sure.
My problem with stack taping is that there is no image whatsoever. just a dry mono mix being.pumped into two microhones. Not to re-hash this debate though. stack tapers like their tapes that's all that matters. it doesn't matter if i don't like em
secondly, tim brings up great points about the kind of frequencies you'll be getting out of the stack. if you ae back in the impact zone you'll get more ambience and "air" in the high end not to mention a better blend between the music and the room. El Barto's recent Gov't Mule tape (2/20/05) is an excellent example of having the 3 things that I believe make great indoor recordings. great image, up-front sound, excellent blend of room sound. All this just because he was in the sweet spot. with a stack tape all you get is an upfront sound, but with the loss of the other two i believe you lessened your chances of making what I and many others believe to be a good 2 channel recording.
you have to remember the room will always shape the sound of the PA. if you have a great sounding room, stack taping would be futile unless your only other option was to set up TOO far away. If you have a shitty sounding room then maybe a stack tape will sound better cleaner. But shitty sounding rooms usually have shitty sounding PA's leaving you with a shitty sounding stack tape, DPA's or not.