This one's a bit of a Jack of all trades, really. The ERLL can be used to reach out and touch someone with the AC supporting them. Obviously, the AC will be supporting the ML at brawling distance aswell. I don't tend to rely too much on the LL at that point, heat could become an issue on the hotter maps. Weapon placement makes sure that you can lose half the 'Mech and still dish out plenty of damage. Losing LT or RT means you'll either be left with two LL and a ML or two ML, a LL and the AC respectively and you could even zombie with a single ERLL if you lose both torsos. People tend to go for the ballistic torso though, so expect to lose your AC and twin ML first.
A very good build. The Misery chassis is proving to be quite interesting, with the 5th Energy slot providing a good deal of flexibility in weapons placement. One idea I've been playing around with (on paper at least) is to put both long range Energy weapons in the right arm. This allows you to peek around cover and engage at long range without exposing all of your mech to return fire. Also, ammo placement is very important for survivability. To decrease the chance of a critical hit cooking off ammo, switch its placement from the legs to the arms and fill the arm critical slots with DHS, as Stalker arm hit boxes are fairly small compared to the torso hit boxes. Although Stalkers are rarely legged, the inability to store equipment alongside any ammo means that the chance of the ammo being struck by a critical hit would be higher (see this link http://www.mechspecs.com/showthread.php?1460-GUIDE-Surviving-in-The-Harsh-MWO-World for a more comprehensive explanation). Ammo capacity has remained the same and I've managed to install the maximum rated engine for the chassis. The armour rating is less than the original build, but all three torso sections have remained fully protected.
Odds of someone accidentally taking an arm off as opposed to a leg are like 10:1. Storing ammo in legs for assaults is basically guaranteed to be fine. I'd be much more worried about cooking off a ton of AC/10 ammo in an arm than a leg. Head is basically the same. If you get critted in the head, you're pretty much dead regardless of if you have ammo or not. It also gets used first, so unless you're not managing to fire 15 rounds before you get headshotted, you're fine.
I rarely get hit in the arms on my Stalkers, so I wouldn't be worried about ammo in there. It's usually the giant side torso that goes kaput and takes the arm with it.
Howbout this instead? Chainfire the LL on 1, AC on 2, SRM on 3, Alpha on 4. You can fire almost constantly and your direct fire guns all share range so if one can hit, they all can. SRM for more dakka.