Just to add to this another surprise I’ve had over the years is the complexity around bypassing!
Ask yourself these questions.
Should bypassing be glitch free?
Should bypassing maintain the plugin latency?
Should bypassing free up processing resources?
Bonus question, should bypassing maintain a perceivable level?
Why do I ask this? because different DAWs have different ideas.
Most DAWs include two concepts.
Normally bypass is glitch free and maintains the same latency.
Additionally there is often an option to enable/disable the plugin to free up its resources.
However some DAWs have only one of these.
Most plugin formats have a way to either announce a bypass parameter or link to a bypass parameter. However not all DAWs pay attention to this. VST2 is a bit of an odd one out that makes things very difficult.
As a result in a plugin it’s often good to offer a glitch free latency maintaining bypass and link it to the host bypass where-ever possible.
Logic is possibly the worse culprit as AU offers a way to link to a host bypass but Logic doesn’t implement it. It does however have a bypass parameter which acts more like an enable/disable (it’s not glitch free and does free processing resources).
You may also want to consider if bypassing your plugin should maintain consistent processing, this can reduce sudden processing spikes that can lead to unintentional glitches.
For me this is a topic that when I first started I had no idea had so many hidden complexities, it seems so simple from the user perspective.
To be fair after the JUCE team have implemented a way to report a bypass parameter which should help in most cases, I highly recommend you implement a bypass parameter and implement the function to indicate which parameter it is.
I would also warn against implementing your own preset manager in a plugin, it’s doable but it’s another one in which you have to think carefully about different DAWs and plugin formats. How does it work with session saves and host presets (you’ll have a hard time telling the difference between the two).