The cost of providing and managing allocated seated means that no LCC is going to introduce it in the foreseeable future.
I agree that there is a risk of violence for those who do not understand the new system. On a recent FR, they had two separate queues for those that had paid and those that had not. In the 'had not paid' queue, people knew that they had to queue early and were standing patiently in line for 40 minutes or so after clearing passport control. So, the airline wins twice: Some pay extra and the others are racing to get on. The old system of boarding by 1-30 and 31-60 etc. has gone and it's everyone in a mad dash to the a/c.
Allocated seating means folks in the bar waiting to be chased out.