Miracle and a shard seem the most reasonable to exchange for other cards. At 36 cards the draws are reasonable, at 40 cards it's also playable (e.g. throw in another quint and destroyer). My favorite mods so far are:
- with 2 dials instead of the miracle and a shard - they give a lot of safety vs creature heavy opponents, and can provide EMs.
- with 2 sanctuaries (image below) - I was thinking how to make the deck more durable vs the hardest enemies - those with perma control and the Black Hole. Sanctuaries give an edge over Decay and Black hole, and also give some fodder vs perma destoyers. I usually waste a few towers, shards and sancts and then safely play pulvy and shield. Sancts also seem to be a safer healer before you can play your Permafrost, because with shards you risk a -1 to water.
6qq 6qq 6qq 6qq 6qq 6qq 6qq 6qq 6rn 6rn 6rn 6rn 6rn 6u3 6u3 6u3 6u3 6u3 6u3 6u7 6u7 77f 77f 7dq 7dq 7gp 7gp 7k6 7k6 7n3 7q5 7q5 7q5 80h 80h 80i
(Entropy mark, ?=sanctuaries)