Thunderlord is great and everything. However, it sucks that the only way I'm going to use a machine gun is if I sacrifice my exotic slot. I wish they would have introduced at least three other machine guns into the game when they released thunderlord.
Also (my opinion) thunderlord isn't that good.
Except for Malfeasance, and sometimes Chaperone or Trinity Ghoul, I rarely have an Exotic equipped that isnt a heavy. If they dont nerf Thunderlord, it'll occupy that slot on 1 character at least for a long time.
The MG has always been a favorite of mine. I cant wait for the Legendaries so I can customize my loadouts with the above mentioned small arms exotics.