I think it can help, to some degree, to try and figure out what the Psychic Maelstrom's angle is: what sort of perspective is the Maelstrom bringing to your Apocalypse World, above and beyond answering the PC's questions?
One way to do this might be to think of it in terms of fronts -- does your Psychic Maelstrom represent a fundamental scarcity? If so ideally it's one that you don't already have in the game -- so it can interact with existing fronts freely, instead of merely appearing to be the instrument of one or another of them. Or maybe, instead of that, your Psychic Maelstrom represents the opposite of one of the scarcities -- your Maelstrom is all about satiation, or generosity, whether in a straightforward or a warped sort of way.
This is different than actually making your Maelstrom a Front, by the way -- I'm definitely not advising that (unless you already have an idea for it). I'm just saying: maybe it would help to think of it in terms of a scarcity, as a way of getting an angle on it. A hungry Maelstrom has a different character than an envious one -- it wants different things from the players, and it provides different perspectives as well.
Similarly, you could use the Threat structure (what does it mean to have a Maelstrom that is a Warlord (Hive Queen), or that is a Grotesque (Mutant), or that is a Landscape (Prison) or whatever. Again, doesn't have to actually be a Threat, but you can use the language (and then borrow the Moves, even, for when the PC's miss.)
Another thing that's already been mentioned is the Questions. Hopefully you've already been following through on the game's advice: the first time the character Opens Their Brain you have to ask them what it's like for them to interact with the Maelstrom. In terms of the aesthetic of the visions and such -- for me, those should be based almost entirely on what the player brings to the table. In our first game we all had very different visions of the Maelstrom, but they ended up sharing certain commonalities -- but how your Gunlugger gets her answers vs. how the Angel gets his, I think you want to follow the players' leads. And keep asking more questions about 'what it's like' until you feel like you've got what they have in mind (or until you force them to have something in mind.)
But apart from questions about the Maelstrom, the sort of questions the Maelstrom asks seems like a really high-potential area to me. I remember one of the first times a character Opened Their Brain, and the MC question went something like:
MC: Who was your best friend/closest ally, back in <previous home>?
PC: Uh... <describes a person and a situation and how it worked.>
MC: Okay. Actually, there was someone else you liked more, but you've forgotten them.
At which point I was like 'whoa!' This Maelstrom means fucking business.
And of course the Maelstrom has particular interests -- it wants to know specific kinds of things, which is where some of the above bits about 'the Maelstrom's perspective' come in. An Envious Maelstrom might tend towards exactly the sort of question described above -- asking about nice things and then snatching them away for its own use -- while a Maelstrom made up primarily of dead children might ask lots of simplistic, experiential questions ('what's it like to do X?' 'what does that taste like?' etc.)