Yes and No. Just because it can be viewed differently by each character, does not mean that they'll not have some unifying features. You can always load the questions you ask them too, ex: "Considering how wet the maelstrom is, how are you filled by it when you open your mind?" The maelstrom will end up being somewhat unified in concept regardless of how each character interacts with it. The Maelstrom has an agenda, even if you dont know what that is, it's always a good idea to keep asking yourself what it might be. Your questions to your players may help flesh this out as well.
Basically when they tell you how they interact with it, they're giving you traits to start play with. Put them together and start asking yourself, why would it do that? When you start to figure it out, and when they do to, that's when it gets really interesting.
As for Experience, "spamming rolls" is certainly not a big deal. Although you should make each roll count. Each roll represents something happening in the world whose results should be determined by the result. So like, just cause you walk up and punch a guy doesn't make a seize by force. That just might be preliminary, you punched him in the face and he goes down. His buddies, who were playing cards across the street get real quiet a first, and then stand up. What do you do? No matter what they decide, it moves the fiction. Do they size them up? If so the questions they ask let you flesh out the threat better, be sure to do that. Do they open their brain? That suggests there is something More going on here then just what meets the eye, what is that? They put it here, so think it up, or ask some questions to wrap your head around it, and then put it out there. Either good or bad, their roll decides. Either way, the world got more complicated. If the player instead just yanks out his gun and wags it over towards the oncoming goons and levels a bit of a threat, a go aggro will control the snowball.
Everything snowballs.
Also remember, they can't call out a move just because. They have to preform that move in the context of the fiction. How do you open your mind? "I light my cigarette and give an exhale. I see shit in the smoke sometimes." Once that's figured, they've got to light up in a scene to open their mind, and others might start noticing that when he lights up.. strange shit can happen. Hell maybe you know that the maelstrom likes to burn shit down or maybe that it tries to manifest in the smoke.. whatever it is. Next time there is a big fire.... maybe strange-ness is all wrapped up in it too. Especially on a miss. I mean, maybe maybe not, but hopefully that provides some potential context.