I have an idea, as the 12th element was removed to create more variety in the combinations, it still is not enough i believe. Every top combo in the leaderboard consists of either Light or Darkness, I mean there's no viable combination without one of these, for example like Earth-Fire-Water-Nature, and i think thats just because all slows require Darkness or Light.
So my idea is to add a slow to the effect of the Quake tower, it does make sense really cause it makes tremors, ofcourse u'll need to reduce its dmg a bit, but i think its doable. Also most of the triple towers can't be build without Darkness or Light, so it shouldn't be overpowered.
Tell me what u think