The only real downside of this variant is the same downside the Battlemaster has... which is Fighters get too few maneuvers.
Most of the maneuvers are situational at best, which means very few people will ever select a good half of them because they aren't worth using their two or three options on them. Precision Attack and Riposte can be used almost ALL the time against all manner of enemies... but how often does a Fighter really need Reach (if they don't already have it from having a reach weapon, or just throwing a javelin instead?)
Personally, I'd give all BMs 5 maneuvers to start with at a minimum (as though they took the Martial Adept feat) and keep letting them get more. Because to my mind, maneuvers are the Fighter's "spells"... and if we are going to let clerics and wizards select from dozens and dozens of options, changeable each and every day... there's absolutely no reason to be so stingy with the Fighter.
Most of the maneuvers are situational at best, which means very few people will ever select a good half of them because they aren't worth using their two or three options on them. Precision Attack and Riposte can be used almost ALL the time against all manner of enemies... but how often does a Fighter really need Reach (if they don't already have it from having a reach weapon, or just throwing a javelin instead?)
Personally, I'd give all BMs 5 maneuvers to start with at a minimum (as though they took the Martial Adept feat) and keep letting them get more. Because to my mind, maneuvers are the Fighter's "spells"... and if we are going to let clerics and wizards select from dozens and dozens of options, changeable each and every day... there's absolutely no reason to be so stingy with the Fighter.