Executor: My point is that there _is_ a cost involved.  250g/0g upkeep for a 6-point researcher is still worse than 150gp/10gp upkeep 6-point researcher for 10 turns.  20 turns if the 150gp mage is sacred.
Also, IIRC, it's -2 rp 50% of the time, -3 rp the other 50%.
And that's not looking at the capital cost.
Is it balanced?  Probably not.  But you can at least argue the point. 
