"Searing Light & Radiant Aegis str gated behind Carbuncle"

Radiant Aegis is completely fine with 30 sec duration. I have played summoner over 8 years and this is skill is actually extremely valuable during prog. Summoner was always the first person who died in the raid if some mitigation/heal was missing. Now I can save myself for using it for every big aoe regardless do I need it or not.

Searing Ligth however is really annoying to use, because some mechanics not allow you to and delaying few globals for it is pretty big dps loss. In hesperos 2 rank1 summoner (before patch) was stacking spell speed so you don't have to delay rotation. Fight does not even have downtime.
If you wanna check akh morn window looks like this