In ThemeTree, we haven't talk or discuss about 4.5 because in life, we're currently busy doing things and handling prolonging clients.
As for the themes, 4.5 has changed a lot and modified a lot by the default theme to the improvements of UI & UX. In this case, all themes will be rebuilt from the ground up to maintain the level of changes they have made for us theme designers.
When 4.5 gets release, please do not upgrade our theme(s) because we're probably busy with other things that we need to attend too and when we have time on our hands, certainly we're gonna get on them.
Note: If you do upgrade because of how much stuff they've put into, then upgrade, but just know from us that this our precaution because some things or more will break the site/theme or modify it to not look like our themes.