Nobody has ever played the rank up dungeon, the titan dungeon or the infinite gauntlet for the purpose of looking for a ""challengue"".
You have to understand that these game modes are not fun for us, they are a burden, because, in order to have fun with a monster, you have to take him to PvP, and, in order to use him he has to be at least rank 3...
And in order to rank him up you have to use him in the rank up dungeon day after day for almost a month.
The fact that you just made things harder/impossible for us just show how incompetent of a developer team all of you are.
You are not getting a cent from me, kisses.
The only possible way to make the thing a fun challenge would be:
no more survival.
Lv, runes and relics that matches the current level of your monsters.
100 cells per node, or a total of 200-400 per monster.
Or even better, an actually survival dungeon where you fight battle after battle the longest you can, with probably 10-30 cells per battle.
Edit: language, be careful or you will be banned for forum rule violations.