5 Mages?

How would 5 mages do in PvP/PvE?
I was thinking speccing them frost for ice barrier and elementals and SHATTER.
Or would a healer be better than an extra mage?

Thanks.

My original group make-up consisted of a lead priest and four mages. Very similair to XZIN. It was a very dynamic group , fun to play and easy to manuever. I did hit a wall with them though.

I had a hard time with the higer end instances. I really needed a tank so I wind up creating a Paly and switched on eof the mages out. Give it a try. Youll love it. Just my own experiences.