Do all of that and we're back to a sane state of affairs where you can join a union if you want to, and the employer is free to either contract with your union or hire somebody else.
With one caveat. The employer may not fund or operate his own "union" as it makes a mockery of free association.
Repeal the Wagner Act and that becomes moot. The only reason employers invented that dodge in the first place was because the Wagner Act forbids more than one union representing the same job types in a union shop. Having a "company union" blocked real unions from organizing in the shop, but only because of the federal statute.