Almost all of the Master of "X" feats include all of SLAs available to the respective class. Master of Light contains only one of the four SLAs available to light-aligned clerics.
All of the Master of "X" feats include at least one area of effect spell, except Master of Wilds and Master of Light (Master of Wilds at least gets 4 different spells, all SLAs, while Master of Light gets only 3 spells, only one of which is an SLA). Area of effect spells are essential in an end game that increasingly consists of very large spawns of mobs.
All of the Master of "X" feats include complete removal of max caster level except Master of Light and Master of the Dead which receive only 10 extra caster levels.
It seems that Master of Light has been specifically singled out in three different manners, and results in being a MUCH weaker feat for clerics than the other feats are for their respective classes. What is the reason for this? Are clerics seen as overpowered versus the other casters? I find that very surprising. Clerics have very few AoE spells to begin with, and are largely limited to low level damage spells (they have only a single damage spell above level 6, and it's terrible.) Receiving access to SLAs with the new enhancement line was a wonderful change to this class, so why are these SLAs not receiving the same treatment as every other casting class? Very disappointing