So what use does a light mech have end game??? Torching cities my friends - this mech can raze a Demolition target in record time, then scoot off to the jump ship before your lance mates get wrecked. Plus its super fun. You can also circle strafe Assaults which is effective, but a little dangerous. I also put this mech into storage when i need to sell up, as it can be put back into action quickly and cheaply
I heard about using lights with flamers for Demo missions. Haven't tried it myself. One thing I really like for Demo is dumb-firing LRM's.