Shorter ranged version of the dance of death, featuring a more forgiving LE325, a better weapons synergy (MRM20 has -10% cooldown, coupled with duration it will fire almost at the same time with the MLs), overall better cooldown but still not excellent for prolonged brawls and the same good old shield arms. More forgiving during a brawl, less forgiving if combat is over 300 meters due to lasers uselessness... Probably the best synergy possible between MRMs and lasers due to MRMs brawlish nature (bad spread, long travel time to target, -10% cooldown and almost same duration) and Lasers (insta-hitting target regardless of distance), so forcing a build to be almost completely close range (<300 range) should perform decently in solos and PuGs.
ECM is good, 34% cooling efficiency on a brawl build not so much... Even with a -10% missile heat generation, MLs are the hottest weapons and probably the most suitable for the final killing blow. I would have a slower mech (and exploit ECM protection) rather than a hot build on such a short ranged build.
Hey, just doing some math here... Before skills, your medium lasers have 3.5 s cooldown and ~.85s duration (with 5% perk) resulting in 4.35 time between shots. MRM20 has CD 3.87 (with 10% perk). MRM40 has cd 4.275 (with 10% perk). Seems to me if you want the weapon durations to line up, you ought to run something like this: