Your opponents can just kill Rubinia to get their creature back and, as a creature itself, it's more vulnerable than enchantment-based Mind Control effects
Sapphire Dragons keep a watchful eye out for any traces of aberrations from the Far Realm, such as beholders and mind flayers
The other issue is the crafting/disenchanting cost of these cards: Personally, what I would like to see done is increase the odds of pulling a golden card to 1 in 4 packs
It's a noble goal, but Sunburst didn't solve any issues, remaining a Limited-only mechanic and the core of one of the worst-performing Preconstructed decks Wizards had yet produced
Even with its low cost, the variety and depth of designs make it a standout choice
Inkay takes 20 additional damage from Grass-type attacks