Leona: Pretty great, avoid all-in Daybreak, just the good units Guiding Touch: Great card, doesn't need Soraka. Sunburst: Mediocre, but removal always has a niche. Morning Light: Bait card, too clunky for now. Zenith Blade: Bad w/ Daybreak; potential with Taric, Zed, Vi, etc.
If you compare Morning Light to "For Demacia!", it costs 1 less and while the buff drops from +3/+3 to +2/+2, it also activates Daybreak, which IMO means it'll be pretty solid in a dedicated Daybreak deck. As Champion spells go, I think it's good.