I wouldn't say they are OP but in my opinion i would say, they are a little bit to strong. Because the burne time is to long....if you hit from this grenade, you have to escape and wait till the burn turns off and you can regenerate your life....and this time is to long. The time you can't fight are about 14 seconds, and this is at a shooter a really long time. (don't say git good or something, cause if your oneshot and challange someone who have full live...yeah, most time you will die^^) This point is only in PvP not PvE...in PvE i would say, the burn dmg and time could be longer/higher. sorry for my english...i know it isn't good, but i hope you understand what i mean.