Firstly, there are some great new features in the 2020 version of KeyTREE - well done!
Wish list - Is it possible to add a selection filter to the database so I can highlight the filtered trees in some way? Maybe put the trees on a separate layer similar to the 'Marked for removal' feature.
I'm thinking specifically of Ash dieback disease and being able to highlight all Ash trees on a site to show the client the possible effects of the disease to their landscaping scheme in the future.
Having used KeyTREE for a couple of years now, I find it difficult to freeze/switch off any tree(s) or parts of a tree(s) that will be removed as part of a development. I think a nice feature might be for trees 'marked for removal' are placed on a separate layer(s) so they can be easily switched off/frozen. They can therefore be hidden in certain viewports to demonstrate the impact of a development layout. I appreciate this is possibly more complicated than it sounds.
I would also like to add my vote to Paul Collins comment above about the draw order for tree labels.