I'm not sure about beta blockers, but Adderall doesn't do well for games - it's more suited to holding down attention on things like spreadsheets. Modafinil doesn't work nearly as well as sleep. It helps in learning, but not so much on the battlefield, unless someone had an all nighter.
A few cups of tea might just do all of these better than drugs would. And things like L Theanine or creatine don't really need to be banned.
I agree with you, unless you have serious ADHD I don't think Adderall etc. would work very well.
I would imagine that Adderall would be useful for TRAINING for games, if you need to practice some repetitive task over and over (I'm thinking of ssbm here). Not that this warrants a ban.
A few cups of tea might just do all of these better than drugs would. And things like L Theanine or creatine don't really need to be banned.