All my opinion so take it as it is:
Tbh I can't imagine anything that would be a particularly dramatic improvement over already-existing products like the Handy, unless it were designed similar to the OSR2 with multi-axis abilities. Short of a multi-axis design, what benefits could it possibly offer over (for example) the Handy? It can't sync better, the Handy is already spot on. Faster or more strokes per minute would be worthless, the Handy already goes absurdly fast. I guess you could improve the sleeve-holding method and introduce a variety of sleeves akin to the fleshlight, but that seems like a stretch to push an entirely new product out for that when there's workarounds with the Handy and Fleshlight has the sleeve market on lockdown.
I'd personally be much, much more interested in a porn-centric VR headset, even though I'm sure the costs involved would be an order of magnitude over a stroker. A VR headset "designed by porn lovers for porn lovers" type of thing. If it's specifically for a niche market like porn viewing, even something like an upgraded 3dof Oculus Go would have potential. Especially considering the quantity of people (like myself) who would love the higher quality screen/portability/etc of a Quest 2 but refuse to buy one and support Facebook.
My other suggestion (sorry I know this wasn't a suggestion thread but here I go anyway) would be a porn game similar to Dezyred...only good. I saw a huge amount of potential playing around with it.
Edit: thinking about it further- multi-axis would be by far #1, but easily interchangeable sleeves and some sort of discount on the annual script membership (once it rolls out) would also possibly be enough to sign me up for a reasonably priced stroker, despite already owning a Launch and a Handy.