Oops, missed the ML on the Skyrays, and your AA comment is well made. However, as they will be skulking in the rear, my point on the GMs still stands - the (implied) tactics effectively robs your forces of up to 50% of their long-range firepower in an army that seems geared up to stand back and shoot.
I still stand by my comments on the comparisons with the marines.
With lit targets, you get longer-ranged shots and still have the equivalent number of close range shots on a skimmer chassis which allows for creative use of pop-up etc to avoid retaliation and CC assaults. The predators
need ATSKNF and better initiative because of their shorter ranged weaponry and smaller numbers (though having two activations is a distinct advantage at times). And I for one don't think the marines are too expensive - just not always used to their best effect (read poor dice rolls

). This does need some other formation to light up relevant targets, just like you need to pay for a Landing Craft to carry Predators, or perhaps Cross-fire to make them more deadly - the different formations use very different strategies and tactics to be used optimally
The comparison with Eldar Falcons is more interesting because I find the Falcons horribly vulnerable, primarily due to their short range weapons and weaker armour. This is offset to an extent by skimmer pop-up and larger formation numbers which together with hit-&-run gives the formation an edge over the more expensive AMHC in terms of raw firepower, but in a straight head-to-head fight, I would bet on the AMHC every time precisely because of the better guns and armour.