Just have the customer keep in mind every 'lines up' for access to the Channel (CSMA).
I usually boil this down to the analogy of line-ups at Starbucks or Tim Hortons (Canadian, eh?)
Mr. Customer would you like to have 199 people infront of you when you arrive at the coffee shop and only one cashier? Or would it be better to have multiple line ups to work through the same crowd much faster? (parallel).
Answer: Of course not ;-) I want short lines, lots of them. I want to be in and out.
Aha, excellent... so lets stay away from loading up APs with 'line ups' of 200 devices too ... even though the (Aruba) network 'can' handle it? Your users will be happier with several, shorter and faster lines. Everytime.
JF