This really depends on who the form is designed for. If this is for your own personal use, then go ahead and open in design mode. If anyone else needs to use this database, then I would seriously suggest that you rethink this decision.

Exactly why is it a problem to have a bound control? I don't think I've every come across a database structure that did not require at least a handful of tables just to supply values for lists. It's quite simple: you just need to make sure that you provide the user with a way to update that list.

If you are going to give any old user direct access to modify the design of your database, regardless of skill and experience, you are going to have some serious problems down the track.