I just got my OP-1 and I really love some of the features. For example, I think we can all agree that the tape feature is amazing. There are so many things you can do with it, and so much versatility for it being so easy to use. I like how you can even do variable-speed recording (shift+rec).
I also really enjoy the sequencers. The finger sequencer is great for doing complex-sounding stuff, and it's very fun. Endless is like a really powerful arpeggiator, but somehow stays simple and easy to use.
My biggest disappointment with the OP-1 is the synths, though. I feel like this is TE's weak point. Even in their early demo videos of the OP-1, the sounds weren't that great. In particular, though, I think that the modulation ("LFO") capabilities are pretty weak.
Reason one: I'm going to be blunt and say it: modulating most of the synth parameters on page 1 doesn't really affect the sound all that much. The engines, even when you change the parameters from one extreme to the other, don't change that much. Shifting the octaves of the keyboard does much more to change the sound of most of the synths than turning the knobs does.
(Henceforth, I will be referring to my suggestion as a "real LFO" or "true LFO", and the OP-1 modulation section as just "the LFO", to hopefully avoid confusion)
Reason two: There is no real LFO. The closest we have to a true LFO on the OP-1 is either using the envelope as a source with the "element" LFO, which kind of sucks since it's already being used for the volume of the sound. Closer still, we have "tremolo", which allows you to do either tremolo or vibrato. Pretty useful, but I feel it's a "so close, yet so far" kind of situation. A saw wave, for example, would open up a much bigger range of possibilities for sound design.
Now, the problem is that that sort of thing would be adding way too much complexity to the OP-1 and would go against the whole spirit of the device, right? Well, here is my opinion about how that can be solved.
When you're messing with a synthesizer on the OP-1, pressing 3 twice toggles the FX on or off. Pressing 4 twice turns the LFO on and off. Pressing 2 twice has no effect. Perhaps a real LFO could be added as a second screen for the "2" button in synth mode. Press 2 to access the envelope, then press 2 again to access the real LFO. Pretty simple, and doesn't add too much extra complexity. Maybe there could be a few common shapes, like a sine wave or sawtooth (I would particularly love to have a sawtooth). You could change the shape (perhaps with a smooth transition between sine, triangle, saw, square, etc) with blue, speed with green, attack speed with white (i.e. to make the real LFO "fade in" rather than starting at 100%), and you would still have the red knob that you could add functionality to. (Perhaps to change reset behavior, i.e. to reset the true LFO's phase to 0 on each note, or to have it "free-run". Or perhaps to add "noise" to it, to make it a bit more random and less periodic).
Even better would be if you could use the sketch feature to draw your own real LFO too! But having a real LFO at all would be good enough for me.
The "real LFO" you edited in the 2 screen would then show up as a source under the "element" modulation of the LFO screen (4). There would be next to no complexity added to the OP-1's interface, and it would stay consistent with the rest of the UI, since pressing 3 twice or 4 twice has functionality.
I suggest pressing 2 twice because I feel like a "real LFO" deserves its own screen, just like the envelope does. There is enough functionality in a true LFO to warrant it. The alternative would be to add the "real LFO" as an option in the shift+4 menu. It could be called "oscillator", to avoid confusion with what "LFO" currently means in the OP-1. But an LFO is pretty complex, and I don't think you could fit all of its options AND the modulation routing options in one page.
Perhaps you could if you added shift+knob functions to the LFO screen instead of the near-useless fine-tuning functionality it currently has. But I think my other idea is much better.
Anyway, that's my biggest wish for the OP-1. I hope TE sees this message and considers it. I love the OP-1 otherwise, and I don't plan on selling mine or doing anything crazy like that. The other features, like the tape and sequencers, are pretty great, very inspiring, and deep enough to satisfy me. I suggest this because I feel that the synths are so close to being on that level as well, and it's a bit tragic that they aren't.
I have a few other ideas for the OP-1 as well, but that's probably my biggest one. If you agree/disagree, I'd love to hear your opinions. Or if you have your own wishes for the OP-1 and ideas about how they'd be implemented without breaking the feel or simplicity of the interface, I'm interested in those too.