I wanted to make this scenario for 2 reasons;
1. The lack of scenarios for the 1st Coalition
2. To see the effect on the French Republican Army of having no leaders at all. After the Royalist officers fled, the French Army was about 1/3 old professionals, 2/3 National Guards. The middle order officers mostly had become émigre, and hadn't been replaced. On the whole I think the lack of leaders gives the Republican army the feel of an enthusiastic but amateurish force.
The Optional rule is listed because in playtest, players didn't like that 50% of the Tactics cards were unusable to the French. So this gives them some mild purpose. However, the scenario wasn't playtested this way, so be warned.
Glory is fleeting, but obscurity is forever.
As you already said Mark, nearly the half of the tactician cards would be useless, if you play without LDR´s,
and this is a big disadvantage (if opponent don´t have such a restriction).
So i would suggest, play with LDR´s, but limit the number of TC´s, which could hold into french hand at same time (maybe only 2).