As mentioned during the Weekly MTG show, most prison effects like Ghostly Prison dont actually protect your Planeswalkers
Commander creatures you own have At the beginning of your end step, exile up to one target tapped creature you control, then return it to the battlefield under its owners control
4 Counters: Add 1 "Six Samurai" monster from your Deck or GY to your hand
SE Secret Rare Ninjitsu Art of Mosquito Marching X SPELL Special Summon up to 2 Level 4 or lower Insect monsters from your hand (with the same Level, if Summoning 2)
A missed opportunity Anytime you make a change in pricing, I think you need to recognize that people will immediately want to know whats in it for them
Important to note here is that the card reads in addition to, so your utility lands will still retain their other other abilities and your lands will still tap for the original mana they were able to generate