not all monsters need high grade earplugs and against those that don't it's somewhat of a waste since earplugs is one of the higher investment skills --- "Me fail English? that's unpossible" -Ralph Wiggum
The only thing you need earplugs for are rathalos and subs. I don't think anything else that roars capitalizes on it, I think of earplugs and HGE as just free hit skills.
Uragaan can get you too during a roar, and I think I. Lagi can get you with a close range electric attack. That's all I can think of off the top of my head though, I've had HGE since rath soul > Helios and am not quite ready to leave it yet. --- Conrad Verner: "My wife was really supportive. She even paid for my shuttle fare off-world." Matriarch Aethyta: *facepalm*