Sorry, but an apple cannot become an orange. A hunter is a hunter and will so remain. Deleting the hunter and creating a warrior is certainly one way to do it.
However, since you get 10 slots per server (cap of 50 total), it might be more advisable to just abandon the hunter and create a warrior. Later, you may decide to return to the hunter. If not, when you get around to deleting the character, you'll do so in an informed way, and do something like selling everything, and mailing the jingles to the warrior.