Like mephi said cougar is beefed up. Because of this it pulls agro real fast. The issue is that the cougar cannot sustain the damage dealt by certain bosses with pots and mage heals.
Now I’m not saying it should be easy and just sit back and heal cougar with no stress but at least have a fighting chance. That’s why for KV for instance I’ll go to the ants because range and can tank him. It would just be nice to use the best summon available since you lvled to 72 to use cougar. Maybe it’s not possible but hopefully it’s looked at and maybe something can be done. Worst case I just switch back to INT with a couple less summons