You can kind of get that type of structure with components and LOAD(): http://web2py.com/book/default/chapter/13?search=load%28#Components
Since the import wizard is primarily for newer users, I think the t_ and f_ are important to avoid reserved word conflicts. If you still want to use it, you could edit the table/field names and then delete all the database files (which will get regenerated on the next run). I typically discourage anyone from using the wizard. I think it's useful, even for newbies, to manually create models.
