The flying lord hovering around an army sniping valuable units is generally bad for the game imo. Yes there are counters, but being forced into bringing those counters is also bland. Proposed change: flying units without predatory senses (or another differently-flavored version) are unable to spot units hidden by trees, stalk, or unspottable.
Why is someone on a huge dragon able to spot a tiny lizard through the canopy below them? Why is flying way above give the same visibility on unspottable units as standing right next to them? You could make some of the flying mounts 50g cheaper or something to compensate. I just think the utility provided by a flying sniping lord could be tuned down a smidge.