The version you are using will help here more than you think.
In some older versions of Data Pump, you could only export up to 4000 character table string. So, if your table names were 19 characters, you could only have 200 tables on the command. Got to add the , between names. This was fixed so you can have unlimited tables in the command. The same was true for tablespaces as well. I believe that there is no longer a limit, so make the table list as long as you want.
So, to help us help you, please list the version and the command.