You asked for a 5-point priority:
Inter-operability of sleeves. I appreciate the “economic ecology” of tying everything together however I would strongly argue against forced incompatibility (did Apple teach you nothing!). If that happens you are putting an expiration date on the project from outset - you won’t be able to be internally self-reliant sustainably.
Reliability. It has to work when you want it and for as long as you want it. If that means a power cable option then so be it…
Portability. It has to work where you want it. If that means USB charged batteries then so be it…(I don’t believe it is feasible to have a desk-mounted product as your only commercial option).
Connectivity. BT or wifi. This has to be solved. Somehow. Whether it is desktop software, phone, fablet or tablet. For me that means VR, and the number of posts on this forum (and on SLR’s) on how to connect your VR device is testament to how much of a problem this is. I am aware this will probably mean creating a bespoke player, however SLR have done a lot of that work already.
Mechanically robust. It has to have the technical specs to reflect on-screen speed and depth. I get the extra options but get the basics right first. Don’t do a https://discuss.eroscripts.com/t/new-fleshlight-launch-universal/20190
2 pennies. In.