The decision to depend on an external device is going to suck in 30 years. This is where the OP1 shines. Meanwhile I have synthesizers from the 70's and 80's that still work well and sound amazing.
My sense is that it doesn't strictly rely on an external device - you can find your way to where you like without a screen... My long-term fear is what happens when the internal batteries get old.
(I love my OP-1 and pile of pocket operators; Teenage Engineering is doing amazing work.)
Maybe I misunderstood the OP-Z manual but I think that some of the functionality of the OP-Z is only accessible if you connect it to an iOS device, e.g. the two features called Photomatic and Videolab.
PS some recent promotional material by TE said that the OP-Z app is iOS only "for now", so at least there is hope that it will become available on more platform.
The battery is replaceable, not sure that it's a big concern. I'd kill to see open documented bindings for wireless interaction, as well as the ability to write custom synth engines, but really doesn't appear to be the direction for them.
This could be reverse engineered. If the Bluetooth connection is encrypted, there might be an additional step involving jailbreaking the iOS device (hard) or setting up some kind of MITM proxy. The rest shouldn't be too complicated. It sounds like TE might be working on an Android port; they just don't want to commit to it.
I have a Yamaha Motif Rack synth, from around 2004. It has software to aid in the parameter settings if you want to make a new sound. It is a advanced synth and quite complicated. The tiny screen and knobs on the front panel is very fiddly to use so software on a computer is a better solution. But I fear that in just a few years the 2004 software will not run on any new computer and I will have to keep old computers around to program the synth.
I have that issue on some current gear, most notably the Yamaha MagicStomp. An amazing pedal, still prized by many looking for certain sounds. Handicapped by windows xp only software that just barely runs on a Win7. I keep an old laptop around for that and 2 other devices. Its not a sustainable situation, and many neat devices are becoming impractical if not imposible to use a decade on.
I wouldn't worry too much about not being able to run the software forever -- after all virtualization, DOSbox and whatever means we can run both recently old and ancient software. But I came to say has no one reverse engineered the protocol and implemented open source software for it?
You do ‘t happen to have a spare CS-80 or Jupiter 8 lying around about to make its way to the trash heap do you? I could take either of your hands, free of charge ;-P