Outside of the Scratch platform, I maintain an alternative front end to the Remix Tree viewer on Scratch: NeoScratchTree. While this viewer isn't perfect, it does fix a few issues from the official tree viewer:
- Trees no longer clip off the screen in larger remix trees
- A whole remix tree can be viewed at once without paging
- Unshared or deleted project metadata is now shown
- Little to no zooming is required to navigate a remix tree
- Can display extremely large remix trees, if given sufficient loading time

I have chosen not to implement project thumbnails, as it'd only serve to increase the loading time and make the user interface more clunky. On another note, some complex trees may have extremely long horizontal branches. To traverse across a large area, click on a red or blue circle.