I actually think when they gave dispel a 8 sec cd or whatever it is, it was actually a huge nerf to warriors who usually need to be spam dispelled.
Only time I think mages actually suffered in arena was mage/disc vs lock/rdruid in tbc. That was unwinnable for the mage, since then they have been s tier for 16 years. To be fair they were still s tier in tbc but actually had a hard counter comp.