TBH it doesn't matter so much that there are tons of BSTs in dynamis. Its that most (not all) people don't bother with cities for dynamis. If you are out to get the MOST currency possible CoP zones are where you want to be. Job Ability proc mobs are by far the easiest way to get the most currency in 2 hours. On Fenrir there is a fairly large amount of BSTs in dynamis at any given time and they are almost all in CoP dynamis. Not sure how other servers are but most of the time there are 20-30 people in CoP dynamis and 95% of them are BSTs.
The biggest issue in dynamis is not the amount of BSTs it is the mobs themselves. Depending on which zone you enter, 90% of the people will go after the same mobs because the other mob types are simply undesirable to fight. For instance who is going to go after Cactaur type mobs in Dynamis-Valkurm when you can just go after Hippogryph, Goobue / Treants and Fungars during job ability proc times. This is how camps get over crowded. Also at 99 even the DC camps are crowded with BSTs, along with NIN THF etc.
Alot of people also have said before just look for another zone or go at another time. Unfortunately things aren't that easy. Some LS like my own have events we like to do at certain times. Which means we as an LS have other events to do after dynamis. So we enter dynamis and make due with what is available too us. Reading through all the posts on this thread there are a number of things that can't happen.
1. You can't limit the amount of people in the zone. Depending on your server population on when people do dynamis you would in fact cut off access to certain dynamis zones. Since there are no more reserving zones you would in fact be forcing people to do zones they are not going to benefit as highly from (ie cities). There is no reason to restrict people from playing and maximizing their time spent for 2 hours.
2. Changing the repop time on mobs. I agree that the repop time should be lower by just a bit or add more mobs to the camps. I'm not sure the current repop time on mobs but dropping it down by 20% would help alot. This way people can actually find a stationary camp and just pull mobs to their respective camp and not have to worry as much about overcrowding as the mobs will repsawn at an increased rate (think sorta like the old bird camps).