Note that a completely inaccurate portrayal of Havok's power is needed to make the shot work. Like Black Bolt, Havok's power radiates in a wide swath unless he makes an effort to concentrate it. Cyclops does not have this kind of "bredth of field". Black Bolt could let loose full force and decimate pretty much the whole battlefield.

Ummm...I thought the ruby quartz BLOCKED the beams(absorbed them?dispersed them?) (as do eyelid membranes) and the visor lets them out in a safe manner by momentarily removing the barrier.

Being harmlessly absorbed or dispersed by a material does make the beams seem like a form of electromagnetic energy with optical propeties rather than a columnated beam of matter. BUT they could also be some exotic unknown thing that behaves like light in some respects.

The beam itself might be a secondary effect where he heats air into a plasma and projects it forward. I dunno.

How do the beams respond to magnetic fields? Are they mostly doing heat or kinetic damage? Is any kinetic damage suffered by a target isotropic or directional? Does it shake stuff apart, pull it apart, burn it, cause molecular disintegration, or just smash into things like a hammer?

Or maybe we could just call it a cool special effect and not pick it apart too much.

<<I've purchased and read the first three TPB volumes of Astonishing X-Men and what I took away from the series was that Whedon made it a point to establish Cyclops as an intelligent, capable, leader who was nobody's "boyscout." In fact, I got the feeling that Whedon was making it a point to build up Scott while taking slight digs at fan favs like Wolverine.>>

Ya see, I liked the boyscout.  In my experience on the net, the term is usually used as a pejorative.  IMO, intelligent, capable leader and boyscout are not mutually exclusive.  Being one doesn't automatically preclude Scott from being the other.
Captain America is a boyscout and isn't he generally considered the best leader in the Marvel Universe?

I've seen Logan fans who don't like how Whedon has handled him.  That's he's underused him, used him for comic relief, stuff like that.  Actually, I thought Logan was the one X Man that Morrison portrayed pretty well.   

Didn't Whedon reveal that Scott "choose" not to control his optic blasts?  That it was actually a psychlogical problem rather than a physical one.
I remember not liking the idea from the sound of it, but I never actually read the story.

<<How do the beams respond to magnetic fields? Are they mostly doing heat or kinetic damage? Is any kinetic damage suffered by a target isotropic or directional? Does it shake stuff apart, pull it apart, burn it, cause molecular disintegration, or just smash into things like a hammer?>>

I think the latter.  Scott's beams are concussive.  They're pure force.