Wise Arbiter

Cleric
Players cannot play spells with Casting Cost higher than the number of lands they control.
1/2
The final hate bear:
mud: goodbye to mws advantage, or metalworker. Golem cames as early as T4, kuldotha 5... but maybe it's not that much hard comparing to a kataki.
oath: no more T1 oath, hard to get a jace, but still it's in a good shape.
control: fow cannot appear before T5. tinker by t3, drain loses power. Jace
gush: goodbye to quickly gush wins.
tendrils: T4 at best.
tezz: good luck before T5 unless you get vault+key.
elves: well, they can always win the aggro route, cannot they?
All around it slows explosive starts, neutralizing mana acceleration. Mana can still be used, but only on certain spells.
Maybe it's best as a Leyline? I think white is the best color, since black or green have a good amount of acceleration. Blue likes pitch spells (fow, gush, mindbreak) and red... well, maybe is the second suitable color after white (in fact I would like to see it printed as red, but white seems closer because of the flavour).
This card would have little impact in non-eternal formats. It would affect Tron in Modern, ANT/Belcher, blue control in Legacy, and the only format with a big impact would be Vintage. It would act like a Gaddock (just turn based), which is already a CC2 bear.
Thoughts?