This is true, but basing the right of application on solely experience is bad. What if a random nerd plays ET 24/7, and gets 40K xp within 3-4 days? This also makes people whore alot more. Since they want to get that amount of xp.
On the other side of the xp thing, People who still play lots, but the less offensive class, Covert Ops, as example, gain xp much slower then medics, engineers, field ops or soldiers. Since they are range, and hitting a moving target is hard, and headshots don't kill 1 hit, so thats a big disadvantage too.
If you want, I could code you a php script that saves you time, it will consist of a database, a form to send in applications. An admin side where it shows the applications, and only 1 application per IP allowed. On the application viewer on the admin panel, it would also show their SL info. And upon denieing, or accepting, an email will be send to the applier with the message of it either being denied, or accepted. All that would be left for you would be checking the logs, and clicking accepted, or denied. I could also code in a rating system so clan members can rate the person.