What happens if I have an acid/base equillibrium and remove hydronium ions until there is 50/50 of acid and conjugate base?
You can't just remove hydronium ions because the solution needs to remain electrically neutral.

You can't just add hydroxide ions, but you could add sodium hydroxide until the HA/A- ratio was 50/50.


  Is this a very good buffer?


It is the optimum ratio of HA and A- for buffering.