I always use this strategy of using card draws instead of loot chests as most of the time loot chests will have those potions or guild tokens. So, if we have to level up the reward cards fast, I feel it's best to use the card draws.
These 1 MANA cost monsters are always fun and in low MANA cost battles and battles with same health rule sets, these will be awesome as we get the enhanced health and these monsters with 1 MANA cost will be like any huge MANA Ones.