Alarak is indeed not friendly to beginners. Having tried both of his major playstyles now, I’d say going Mech is easier, but Ascendants is more effective and more fun (albeit more complicated and difficult). But I can see why he’s not popular, he’s certainly not the sort of commander I’d pick most of the time. But he definitely deserves more credit, he’s genuinely fun to play once you get the hang of him.
He does admittedly have more trouble with supply than any other Protoss commander so far, so that does make him a bit less fun, but he’s still very good.