So the people that don't have a surround sound, or want to enjoy this when it comes out on Blu-ray won't be able to fully realize the quality of his bat-voice? I myself won't be affected since I have a pretty decent audio setup, but creating a voice that can only be enjoyed by those that have superior sound systems sounds like a bad idea. 
  
 I'm sure this WILL sound amazing in larger format theaters, but what about during repeated viewings on a smaller format?
		
		
	 
I don't think that's what anyone is suggesting. We're just remarking that it sounds better and more befitting of that scene when played through some kind of surround sound system, as you get more of the "full effect". That's not to say that the voice automatically sounds bad when played through your laptop or phone, but obviously that's not the way that ANY aspect of the film itself is truly meant to be seen or heard. 
I mean, it's true that some general sound elements (and aspects of sound mixing for films) are lost, or not fully realized, when played back on some kind of smaller format device, which is sad but also unavoidable. That much can be said of nearly any film, to some extent. You play back The Dark Knight Rises on your laptop and you miss out on getting the full effect of many of the sound effects, the booming beats of the musical score, the full effect of hearing every nuance of Bane's voice, explosions, etc. 
A BvS example I can point to is actually the very first teaser trailer. If you watch that on your laptop, what you hear at the start of the trailer are the voiceovers by different characters and news people giving their varying opinions on Superman. But when I saw that in the theater for the IMAX, each  line of dialogue from those voices came from a different part of the theater, from the left side, right side, behind the audience, etc. It was like the characters were standing on each side of the theater, divided, and arguing about Superman's place in society and what he stands for -- which was a very cool effect that is pretty much lost when playing it on your phone or laptop. 
My point is that, no matter what, all sound elements from films are enhanced in the theater or with a home surround sound system. It's virtually unavoidable. When you choose to watch something through a smaller format, everything from the picture to sound will be exactly that -- smaller.
In regard to Batfleck's voice, hearing it through he crisper, clearear, and louder format will certainly give it a bit of a different effect -- especially if they tinker with its modulation throughout the film. Reverb and echo/delay effects, for instance, will be more pronounced, as will the background sounds and musical score. 
I also feel like we should probably wait to hear more than one line in context -- whether it be during the theater experience or via smaller format -- before declaring the voice a resounding success or a dumb, bone-headed mistake.