Tbh I would rather prefer to have continued to pay for dungeons than have the main spine free. I used to love paying for the dungeons, it was exciting. Bought em all including the ctf/pvp maps as well before they were free so it is normal to me. Subscription would be cool but 10-20 bucks max.
50 to 75 plat per dungeon would be plausable to many imo. Now the dev team should release pvp n ctf maps for 20/30 plat as well for extra revenue too every time a new dungeon is release. Granted the dungeons are new and intricate