Well, the first thing that occurs to me is, if Aether is invisible and intangible, how can Hermetic Magic target it? You might be able to get away with this using Intellego, because Intellego already bends that rule. Then, if you can target it with an ongoing Intellego spell, you could then use additional spells on whatever Aether you were then perceiving.
Muto Aether spells would allow you to make it visible, tangible, and move in a way other than circular, though I'm not sure what benefit that would have over Muto Auram magic. Rego would begin by accelerating or slowing its movement.
Aether passes through objects, including people. This suggests that, if you could transform Aether, you could do so while it is moving through a persons body, which seems a particularly high level, difficult, but spectacular way to kill your heavily armored enemies. If you can see Aether, probably with a Muto Corpus effect, this might allow you to see through objects.
Instead of making a spell to transform Aether so that it is visible or tangible, you could use MuCo on yourself to allow your eyes to see it and your body to interact with it. This might make a good escape spell, an alternative to ReCo transport magic, though because Aether moves in circles you would always move in an arc (barring additional Muto Aether Magic), and it would make it easier to target Aether in the first place.
Aether that can be interacted with is a potential power source; if you can transform your mill so that it interacts with Aether, the mill (or your windmill or whatever machine you hook this up to) never runs out of power. Similar effects can be created with Rego spells, of course, but for a Muto specialist this might be more efficient.
If Aether is a medium that carries something (I don't know what Plato says on this topic, and I can't stop thinking of the Victorian Luminiferous Ether theory, which postulated Aether as the carrier for light), destroying it would have interesting, if brief, effects; the Aether would probably flow back into the affected area, so your Perdo spell would be noticeable only for a moment. Similarly, creating Aether is certainly possible, but if it can't be seen or felt, it might not be much good.