I've tried multiple times to reverse engineer our system with has ~10 schemas with ~200-500 tables each and a few hundred packages and procedures. It has never completed. Where do I go to see what is killing this? I'm assuming this product is built to scale to larger systems.
Check response time of your server using ping - for local network it's 1-2 ms, if you get more it'll impact the import too.
If there are no references between schemas then you can import each schema in separate relational model.