Radiant Destiny becomes an Always Watching, which was a great pairing with the exert mechanic (or any creature card really)
For example, if an effect copies a card in exile and allows you to cast the copy, casting that copy will cause Ghost-Spider's triggered ability to trigger
Eight mana for a 5/5 flying, lifelink, haste, exalted creature is fine, but being able to convoke this onto the board faster thanks to your army of vampires makes this a fun bomb to drop
Vv'viza remains furious that the Uthros Combine is still entertaining information from Mm'menon, a contention that can likely be traced back to their longstanding rivalry from their days in the Administration branch
Effects that modify or replace the cost to cast a spell (such as flashback or casting a spell without paying its mana cost due to suspend) don't affect the spell's mana value, so they won't change whether Lavinia's first ability restricts that spell from being cast