If I understand your question, you are asking why there is no simple rendezvous with an unmanned vehicle mission. Historically, the Gemini 4 mission was the first attempt to rendezvous in space, by rendezvousing with the spent booster of the GLV. Despite having the same orbital parameters as the Gemini capsule, this rendezvous was unsuccessful for a number of reasons:
1) NASA engineers had not yet worked out the idiosyncrasies of orbital mechanics involved in rendezvous
2) The stage was dumping its residual propellant, causing it to move around in various directions relative to the Gemini.
3) There were only two running lights on the stage
4) There was no radar on board Gemini
In short, at this stage of the space program rendezvous required/were greatly assisted by using special-built vehicles, with the appropriate systems. If NASA took the trouble to build and launch such a specialized target vehicle, it might as well do a docking (as it did with AGENA). However, to do so without having gained experience with a rendezvous would cause a negative impact on the chance of success, as evidenced by Gemini 4's failure to accomplish such a rendezvous. IMHO, accurately reflects the NASA mission planning-without the experience of Gemini 4, AGENA would have had fewer running lights and the orbital mechanics may have not have been properly worked out, resulting in a lowered chance of success with a rendezvous mission.
I've been looking for a Gemini Duration Level 2 without EVA/docking and not finding one. I see that docking requires rendezvous first and I only see the two manned (Gemini 6/7) and not one with an Agena. And I'm wondering why you get a penalty for not doing the Gemini 6/7 mission - that was NOT NASA's plan, Gemini 6/7 was the result of quick thinking after the planned docking flight's Agena didn't make it into orbit.