As much as SE loves nerfing WHMs (Holy nerfed 2x, PoM buffed....then nerfed, SS nerfed), WHMs are still in a good place in 3.0.

Asylum provides powerful sustained AoE healing which helps immensely with your mana management.

Assize has an extremely unique damage component in that it is very high potency (300), and it has the range of a LB 3 (15 yalms), in fights where they are multiple adds to be killed, but are spread just far enough that you can't AoE them down (Garuda's plumes, Ifrit's Nails etc), a well timed Assize is wonderful.

SE has also started to explore encounter mechanics where bosses take extra damage for a limited period of time before the next mechanic (Bismarck's jump on his back and free damage, Ravana's free damage when he's charging his next move).
In these limited period, a WHM's DPS is actually more valuable compared to a Scholar/AST's DoTs, as WHM's DPS are extremely front loaded compared to the other 2's slower burn, this allows WHMs to pump out more DPS in the limited amount of time.