Regarding the debate a few pages ago about lights remaining useful, that discussion has
kicked off on the PDX forums too (and was a regular on the old forums and since the original design goals for the game were announced) and I saw somewhere that the extra sensor range they had in the beta may be gone now.
Which leaves their advantages as initiative/speed/defense bonus/cost - although only cheaper to repair as operational costs are the same, and given armour is free and you only pay for structural damage more heavily armoured mechs may end up cheaper, depending on how well one plays with the light.
But it's worth remembering the 'Ace Pilot' advanced skill, which allows you to shoot or sensor lock, and then still move afterwards in the same turn. The tactic where one uses reserve to nip in, fire with a light, then go first to escape in the next round is pretty common. But Ace Pilot means you can get in with your Jenner, fire 4 mls into someone's back, do the same next round and still get out. Can see this being used by decent players to be extremely annoying - and effective - in pvp.
Of course, with the paper-thin armour, they just need to get it wrong one turn and a bigger mech or long range specialist could rip them apart, so it does need to be carefully judged.