There are a lot of Adventures in this set and doubling them is huge
Its interesting that you can attack with it and tap for mana later because it has vigilance, but unlike normal manlands, it stays as a creature, so its more vulnerable to removal
Whilst it could certainly benefit from additional mechanical complexity, more cards and tools to help adjust the pace (at the moment, games move very quickly), many of these problems are indicative of its infancy
Later in the game you should be able to pay the escape cost, especially if you have any amount of self-mill (dredge, Im looking at you)
If youre blocking an opponents creature with trample with your own creature that also has trample, they dont cancel each other out
For that reason, we decided to give one slot to the most expensive of the Common Zodiac cards, Zodiac Rat, and leave it at that