Agreed, I use underhooks all the time, especially against taller opponents and I do throws from that position as well (this is under muay thai rules too). Getting the underhooks are a important skill that transitions well to wrestling.
Its not like Western MT seems to care about this change so i don't really either. I used underhooks for 4 or 5 of the clinches in my fight and scored two really big illegal takedowns so i'm a fan of them still :P.
Here's a good example of a "post-rule-change" fight at Lumpinee. The referee breaks the fighters up when one fighter (usually Saenchai, the shorter guy) grabs the other (Petboonchu) around the chest/waist, and whenever activity in the clinch otherwise slows down.
Saenchai vs. Petboonchu
This was s a great fight. Enjoy.
I've always though of reaching for underhooks as a pretty dangerous way to escape the plum, if someone already has it cinched up. It gives a pretty open window for a knee to the chin.
Originally Posted by TheMightyMcClaw
Depends if they've broken your posture yet. If you are bent over in their plum any way to escape is going to be dangerous. My favorite way is to fall over backwards while protecting my head with my arms and even that has a good possibilty of getting soccer kicked in the head on the way down.