Just as I say to the people who want different reverbs - be specific about how existing blocks and block combinations don't come close. Say exactly which additional parameters you want exposed.
That would be too much to list. And as said, it's not even anything specific in particular. I could have fun with many variations of them. But as you've asked, some examples:
- Envelopes, LFOs and input level to control some parameters (but these should be a general thing allowing you to control pretty much anything).
- Dedicated controls over resonance and cutoff.
- Freely adjustable amount of taps and time, level, pan, tone control per each tap. Ideally add filtering, pitching and reverse per tap.
- Diffusion parameters to smear delays (Deelay does that quite nicely and it's just as easy to access as it gets).
- An envelope shaper (straight after the input), would allow you to nicely get rid of some of the pesky attacks.
- Possibly further effects on either each tap and/or nested in the feedback loop and/or the overall delay (ideally switchable pre/post). Some dirt in the feedback loop of a delay already goes a long way. So do filters, modulation and what not.
- Multiple delay engines (more than two that is) under one hood, including selectable crossfeedback options between all of them.
It won't be required to have all of these in one delay, but I also wouldn't mind. Yes, that'd be way, way too complexed for the current lineup as the editing UI isn't suitable. But this is defenitely one area where a touchscreen (and a new editor as well, obviously) comes in incredibly handy, as it could allow folks to quickly access a plethora of additional parameters without mad page flipping (or scrolling). Or rather, tabbed/swipe page flipping could become much easier. I'd actually prefer clickable tabs on top/bottom as you'd just click on them instead of swiping through multiple pages.