No one I believe, it would not be good idea to have an official leader of a regiment.

First of all part of the reason that the company system was implemented was who wanted to play as one unit wouldn't be disappointed that it was already taken, now they will have 10 chances. Secondly, people would not want to 'arbitrarily' assigned a leader, for many reasons such as not liking the leader or other companies or just not wanting to be closely associated with other units.