Best thing for you to do is to give as much info on how you would like the scripter to code it... example... a druid to gain 100mp and 10dc (extra skills maybe?), knight to gain 100hp and 30dc(extra skills maybe?), etc. etc.
that would help them out a lot more. Cant just expect them to script it and it will fit into your server. Remember all servers have different rate/stats so customising the sub class is quite critical.