>Even with line of sight laser comms?
Laser Data Transmission is unreliable when both transmitter and receiver are both pitching and rolling at rates unpredictable in relation to each other.
Unpredictable is not something you want in your self-defense grid when missing even a single packet can have devastating consequences.
Also, the point of the ship in question is to be as near invulnerable as possible; there is no point in such a ship if sinking the comparatively extremely vulnerable escorts not only mission kills the ship, but causes the loss of tens of billions of dollars of (at this point) basically unscathed capital ship; the ship must be self-reliant enough that at the minimum it can stand and fight until replacement escorts arrive, but the ideal is that its escorts are smaller, highly defensible (if not almost as invulnerable) ships - which makes this sensor issue a moot point anyway, since you still have to protect sensors somewhere
>How effective are Aegis networks against aircraft without predictable courses?
This is a hard one to answer, because to a certain degree AEGIS and other similar systems exist specifically to make unpredictable threat trajectories (/courses) predictable.
Even wildly maneuvering missiles (the most unpredictable of all aircraft) are to a certain degree predictable, because you can reach a conclusion on where the missile will be based on where it is, where it was, when it was there, and where it wants to go.
In short, the missile-knows-where-it-is.mp4 but for AA targeting.
While AEGIS is getting a bit long in the tooth, from my understanding it continues to do its job well as long as the entire system is well maintained, which is unfortunately becoming rarer and rarer.
>Are ships' anti-air somehow more effective against maneuverable targets than the questionably effective land-based batteries
Mainly due to the sheer number of advantages that sea-based platforms have, such as raw available bulk, sensor size, known friendly locations, the ability to just assume the threat already knows about said friendlies, and the generally wide open spaces that are the open ocean (even around landmasses, the water is generally far more open than where land-based systems have to act unless they are in a desert).
Even the shortest detection time (short range, hyper-sonic sea skimming missiles) IIRC gives the ship between 9 and 12 seconds to react to the threat. 9 seconds is an eternity for a land based system, which usually has around 4 to 6 seconds.
Land Based fixed installations (such as AEGIS Ashore) tend to have roughly the same capability as sea based platforms, however. Advantage of being a prepared defensive location that any given enemy is well aware about, no need for concealment and you can have those massive radar arrays blaring wildly. A Patriot/THAAD or S-300 battery would get SEAD'd in a heartbeat if they were to try the same.
Obviously, all of that is just as to my limited understanding. Not a land guy.