I’m sure you don’t mean it, but your post does read as though you feel you should have some entitlement that free software with free support works exactly as you wish.
I’ll read it as a suggestion 🙂 🙂
bbpress is not written by me, and is intended as a light forum plugin, indeed they say ‘We’re keeping things as small and light as possible while still allowing for great add-on features through WordPress’s extensive plugin system. ‘
I’ve written the style pack plugin to add many things that users have asked for, but I’m just a guy in his kitchen, doing this for pleasure and for free.
I added the forum thumbnails quite a while ago, as forums are generally created in the backend by admins who can load a thumbnail to the custom post type.
Topic thumbnails are harder, as they are generally created by front end users, and to add the ability to add thumbnails on the front end is not there, so would need coding, and then you hit lots of code to control what is uploaded etc. It is all quite doable, but not something I’m interested in doing at the moment.
The same would apply to the ability to create grids, masonry etc.
sorry, but that’s the way it is.
Regards
Robin