Nitpicks. No showstoppers but things that may be worth optimizing in the future.
- The interface does not scale
What should be expanding is the graphical representation of the room at the very least. Plugin folks are getting dumped on for a reason for having non-scalable interfaces in 2022 
.
- Configuration options need not be visible at all times
This concerns many of the non-automatable stuff on the interface. Output configuration, number of input channels, LFE checkboxes
- Tooltips or in-plugin documentation is missing
I find the manual hard to read for this plugin. The description is compact like a block with little formatting for readability, fairly short at that and finding specifics would be quicker with a better manual structure here.
If you can't find what you're looking for in 10 seconds, it needs to be improved.
For example, what the hell is that blue colour doing on the Input sections "X" field that appears sometimes ? What does that mean ? What does clicking on those fields do ? Why do I need to ask this question? Tooltips could help ? Just a tidbit here and there.
Most other things explain themselves very well on this plugin IMHO.
- Wasted space
The space used on the graphical representation of the room, the place where the user is likely to spend the most time in when opening this plugin does even account for a quarter of its overall space.
I do suggest taking a hard look at the interface design to make things more efficient, focusing on the things people do the most. I guess this is the first version of the interface. When you're ready, I'd love to see some improvements to its interface, so
- The graphical display is the dominant feature, and scales with the plugin
- The most frequent actions of users are made more efficient. I will not pretend to know what everyone does.
I pan one or two-channel sources in a surround field most of the time. I do not require numerical inputs, but visual feedback of what I do most.
I think I've never used those three configurable dropdowns where you can push things around.
The problem with that is you can only operate those with a mouse. They're not a parameter, whereas on most panners some of these ARE parameters. I'm currently designing a fader-based CSI zone for the parameters I use most often on it. That'll give me better feedback than the interface of the plugin currently does.
You can't see the LFE and the Divergence of each puck/input-channel at the same time for example. On an OSC surface you can, with CSI. Perhaps you can with Reapers OSC, but that seems a LOT harder to do.
That reminds me, making an interface with OSC is not fun in the slightest. I use Lemur that just sends OSC commands, but since Reaper never sends feedback to just binding such commands to a parameter(selected track-style in this case), I have to rely on the tiny little MCP versions of the plugin showing me what's going on. And there's lots of holes in the OSC implementation, like Send mutes(for the x-th time).
Enough. Back to work.
ReaSurroundPan UI Nitpicks
Linear Mode
