They need to add to the spells we already have. Cures, gaining a potancy at certain levels as a job trait would help, not based on skill, just as levels.
Say lv 25 +1%
Lv 45 +2% (total 3%)
Lv 65 +3% (Total 6%)
Lv 85 +4% (total 10%)
Lv 99 +5% (total 15%)
this does not go towards the Gear cure potancy cap
Make the regen series of spells offer a resist sleep trait, afterall restoring HP wakes you up, so restoring over time "should" wake you as well, but i;ll take a resist sleep as immunity to sleep for 60 seconds (or more if you keep regen on) is a tad broken.
At 99 give us a trait that makes barspells sometimes nullify damage of the same element, similar to the af3 piece if its 2% of the time, it would be cool, don't want it to be broken, but barspells can be unreliable sometimes.

We are getting holy 2, which is about time, but give us Banish 4 as well, we are currently the only dedicated mage that does not have a tier 4 nuke.

Give us Protect 6 and make it grant a direct damage taken number instead of defense.

There is a lot they could do to make whm a really dependable healer, i just hope they implement it correctly.