Suppose you need a super troop in your cc. You send out a request and you wait.
Now, say you got 50 people in your clan. Not everybody bothers with super troops. From those who do, 1 out of 9 will have the super troop you need (because there are 9 super troops currently, but this can only get worse as more and more super troops are added). And out of those who do have the super troop you need, how many are going to be online at the time of your request?
In other words, if you request a super troop (and your clan is not OneHive or Vatang or one of those clans anyway!), be prepared to wait for ever to get it.
There is a simple solution to this problem: one gem donation could be extended to cover all super troops by default. In this way, players would not have to wait for ever, SC would get some extra revenue, so everybody would be happy.
At least in my clan, one gem donating is pretty mainstream, though I realize in other clans it may not be the case. Still, I think what I propose is an elegant solution to a more and more pressing problem.