Some random thoughts...
For those who don't know, the Thai version of the double collar control is often referred to as the "plum".
Just grabbing the head is not enough. You need to know how to apply the Thai clinch properly. This includes controlling the distance, breaking the opponent's structure, manipulating his balance, and countering the standard counters (which include driving in for takedowns).
The Thai clinch is useful not just for applying knees, but also for setting up elbows, other close range strikes, and some takedowns.
Properly applied, the Thai clinch is actually a pretty good platform for countering takedowns, but as I mentioned before, you need to know how to use it for that purpose.
You need to know when to give up the position and transition to something else. If you blindly hold on for dear life when your opponent starts winning the battle for structure and posture, then you can get into trouble. The best clinchers will transition smoothly between the double collar tie, other clinch positions, and disengaging from moment to moment as necessary.
As a couple of people noted, there is a problem in street application in that the position is not good for monitoring for an opponent pulling out a blade. Not saying you can't use the clinch, but you don't want to hang out there very long, especially if the opponent can maintain sufficient posture long enough to deploy a knife and you can't see his hands.
Wrestlers are good at countering head control, so if you want to use this clinch effectively against a wrestler, you need to be pretty skilled at it.
If you've never worked with someone who is good at the Thai clinch and been in that position, it's probably a mistake to explain the counters you think would work. Your ideas are ... unlikely to be as effective as you might theorize.