Well one other thing to keep in mind is that monsters in 4E seem to be intended to be in mixed groups. So rather then having say 6 kobold dragonshields, you'd rather have only 1-2 dragonshields and let the rest be slingers, skirmishers, wyrmshields, etc. Not only will the group have greater synergy, you will only have to keep track of 1 or 2 marks which anyone should be able to do.
Or to put it another way.....if multiple marks are annoying for you to keep track of then don't use multiple monsters who mark. You only need so many soldier type monsters anyway.
Or to put it another way.....if multiple marks are annoying for you to keep track of then don't use multiple monsters who mark. You only need so many soldier type monsters anyway.