It’s not really a wish-list item, but really an update request for the website.
You should update the online thermostat compatibility checker to reflect actual compatibility if you add a C-wire. You should have a “result” that says “compatible, only after adding C-wire”, instead of saying a particular setup is “not compatible”. This would save countless calls/chats to tech support to find out if your setup can be used with the thermostat, and lots of potential lost sales when you inform people their setup is “NOT compatible”, when it is indeed compatible after adding a simple c-wire add-on kit.
You should also consider adding a c-wire kit for your thermostats, as this is a common requirement on many older systems. Something like this from Wasserstein: