If i remember doesn't this also give you something along the lines of the power strip back in the day? I remember ATI/nvidia cards with certain drivers had the power strip feature, and it would leave a 2 pixel edge on the side of your screen so when you got flashed you could still see.
The 2-pixel edge on the side of your screen, when flashed, is yet another glitch of enabling Alternate Pixel Center on an ATI Card. I remember some folks claiming that they used this, but when I tried it while flashed, it didn't really help, as this line was way too thin. I concluded that I do much better by simply using my memory when flashed (I can be pretty BS at it, too -- muwwhahahah).
Powerstrip was for old CRT monitors, don't think it works well with modern flatscreens
Powerstrip was never all that good to me. Personally, I used to prefer Nvidia's 'Color Correction,' as its features and controls felt like a relatively natural extension of the colors your monitors already produce. Powerstrip, on the other hand, feels as if something is being layered over your monitor. It hurts my feelings -- ESPECIALLY today with my ATI, because I can't do ANY Color Correction at all, as there's some stupid glitch that allows me to change my Desktop colors, but as soon as AA is loaded, those CC settings do not, in any way, affect AA; in fact, it even brings the desktop color back to default. And it's DARK. :-/ In-game gamma-brightness binds, and my monitor's brightness settings, simply aren't enough, but I've long gotten used to this darkness in AA. And worst of all, Powerstrip can't even fix my darkness issue; it does the same thing, so I guess I'm just S-O-L in that respect. :-/
Good point. Moreover, that pixel alternate setting has been removed from recent
catalyst editions.
Many people don't use Catalyst, though. It's too bloated, so, instead, people will opt for ATI Tray Tools. I use ATI Tray Tools; it gives a lot of control over FPS-increasing tweaks, enabling multi-core support, and a whole plethora of other performance settings -- all in a tool that's small, convenient, and straight to the point.
I thought AA Devs added an option to disable Shadows cause they are buggy and can bee seem through walls and other stuff, wich give advantage and isnt "realistic" 
and this is a Game/Engine problem
, as you said the black boxes are just you "exploiting" 
Yeah, they removed the "Full" option for Shadows in versions subsequent to 2.5 (or maybe just 2.7 and onward), because of the big, boxy, wall-glitching shadows exploit. Yes, it's a game-engine problem, but only when it's in conjunction with video cards that, inherently, contain those Alternate-Pixel-Center (and similar) capacities -- which means at least ALL ATI Cards, old and new.
Back in 2005, I had an Nvidia Card (one of the 6000 series, I think the 6200) that has these humongous, boxy shadows. The ATI Cards were the prevailing "It" thing, but my 6000-series Nvidia card produced shadows that were even crazier than any ATI Card, and only two known people -- me and an old British invite player, "Trig" from uNk (Team uNknown) -- had these mythical Nvidia shadows. So it wasn't exclusively an ATI problem, and it still might not be, depending on people's rigs and tools. The best way to deal with this is to disable access to "Full" Shadow Detail. CVAR checks could easily do this,
but some players have a difficult time conforming to new CVAR standards. This might frustrate some people who don't check the forums, are not well-versed in figuring out why they got CVAR violations, and haven't ever 'changed' too much about their game. And I would just hope that these players wouldn't give up after receiving their notification to conform to new CVAR standards.