I have tested too many matches against very good opponents to believe that it will take down the Mythic Championship
Basic lands (Plains, Island, Swamp, Mountain, Forest) are crucial
Another issue with white is that its most impactful plays tend to be stax pieces like Drannith Magistrate and mass land destruction like Armageddon, which many casual pods soft-ban during their Rule 0 conversations
Typically Iona is found in Oath decks although she is OK in Reanimate if you know she is going to be particularly brutal for some people at the table
Standard is our only rotating format, and while keeping it fresh is important, we also feel that there's a more effective middle ground. In my opinion, this also makes new cards a bit less impactful (at least for those playing the killer decks): as shown by non-rotating formats like Modern, Pioneer, and Explorer, the bigger the card pool, the less impactful new cards tend to be