90% of the time when we get rendering issues, it is file-specific. A main part of that problem is that it can simply be one symbol, even something miniscule like a screw or nut used repeatedly as a symbol, that brings the entire application to a crawl.
This isnt that "Users are doing it wrong" but it IS a different issue every time. recently we isolated a problem where Sweep objects were defaulting to an insanely small seg value which caused even basic sweeps to create hundreds of thousands of vertices which would cause problems all over the place. That one was easy enough to address in service packs/releases but its just a tiny piece of the puzzle.
Im still tackling any files I get with rendering slowness, but there are a LOT of different things, compounded in files that are brought from versions pre-parasolids (anything from before or during the 2008-2009 era) that can cause the exact same symptoms of slowness and crashing.
Any time you come across files or a workflow that leads to slowness, get my attention and we will work through it. Engineering is working on MANY tasks that will all be a part of fixing this, but a lot of those tasks come directly from specific cases like these and every little bit helps.