I've been playing Frontlines with Ninja for a while now, and I'll agree that I've yet to find even a small use for Malmsight. It should be a fairly long duration buff (with a CD maybe 2x longer than its duration) that adds all visible (as in, not hidden) enemy targets within a certain range of radius of the Ninja to appear on the minimap (and zone map) for all players in your party. Or maybe even a passive that's always active with the same effect.

Detect, however, is quite useful. It's niche, sure, but useful. I use it when scouting bases, or as soon as I open in a big battle for a node (as to catch hidden enemy Ninja before they can open, and thusly aid my group). My only problem with Detect isn't that it's a useless skill, but that there's really only one class with Hide, anyway - Ninja. Once more classes get to use Hide (if any more are to come), then it'll become a bit more useful.

Also, Detect can NOT be replaced as a scouting tool by any other AoE. Its field of effect is HUGE. No damaging AoE is that large.