Here are my 2 cents:
(all of this relating only to playing in PUGs)
I think that lights are the significantly harder class to play. For several reasons:
1) It quite easy to do decent damage in an assault mech. You stick with your team so you can't get zerged and train people down with your weapons. On the other hand you have to work quite a bit to have a decent impact on the game in a light.
2) The playstyle of assaults is much more intuitive and easy to learn. You look for 1 on 1 trades, use corners and ridges to win peek-a-booms and bully isloated targets with superior armor and firepower. Lights have a much more demanding playstyle as you constantly need to "steal" damage from the enemy by shooting unaware targets and being in the right place at the right time. You can't simply trade with other mechs. You have a lot of mobility, but it's hard to use all that mobility to create a significant advantage for your team.
3) Both classes require good positioning from the player, but positional mistakes are much more punishing in light mechs as you can get blow up with a single shot or lose critical components/weapons. Yes you can get zerged down if you are isloated in an assault mech, but that kind of mistake is much more obvious and easy to avoid than simply poking a ridge to look for the enemy and getting direwhale'd.
4) While lights can seem OP in the ending stages of a match when they just clean up or when they poke and poke you the entire game with ER LLs, the truth is that it's the 100 ton assaults that dictate the pace of the game.
Imagine that you are in a light mech and there is a skilled oponent in a Dire Wolf and assume your teammates are of matching skill. The truth is, he can kill your team faster than you can kill his and if he secures an early kill lead for his team it's very difficult to come back. This is why I think it is generally harder to carry and play in a light mech.
P.S.
I'm not saying light pilots are more skilled/better than assault pilots I'm just saying it takes more effort and much more try-harding to do well.
Edited by Marmon Rzohr, 29 January 2015 - 08:46 AM.