You know, quite honestly, the idea isn't too bad. Try this take: Upped the engine to an XL400 for super speeds, put on Endo Steel for extra weight into Heatsinks, dropped the armor to 480 and dropped two Large Lasers, in order to fit 22 total DHS. The playstyle is run around like a jerk at 84 KPH in an 85 ton Mech, and shoot at people from 200-800 Meters. Weapon groups are easy 1) Left Side 2) Right Side 4) Chain Fire Doing a 1-2 combo so that you don't get ghost heat means you're putting out 36 points of damage every cooldown without a lot of fear of overheating. Got over 700 damage my first match. The biggest advantage of this build? There's no "shock" weapons, like ACs, SRMs, or PPCs, so distracted targets likely won't even notice you're coring them out.
Another, under-rated advantage is that you don't care about the arms so you can use them as much as possible to keep those precious side torsos protected as much as possible.
Not a bad build, but I would personally strip off 3 tons of armor from the legs and arms, and throw in 3 more heatsinks since you have the crits. If you don't want to decrease your armor, you could alertnatively add in Endo which will let you install another heatsink, though you're left with 3 tons and only one slot, which I guess you could use up with an MPlas (or maybe a Command Console?).
I was using this build with a smaller engine and two ac5's, and it is beast. Runs hot, but good temp management makes it doable for this and the D. I run pretty much the same build on the D, but have been farting around with LPL's: Fun. Easy. A bit more zing: More juice and more heat management required, and no AMS or BAP, but still a killer. I also like to switch out a ML for a TAG sometimes, for spotting and racking up dem bonuses.
I've been running this build but with 21 DHS. It's a lot of fun! Put left hand lasers on the left mouse button, right hand lasers on the right mouse button, chain fire both groups and melt faces!