It's probably a pretty strong choice for a Bladesinger Cleric build, but Bladesingers are already MAD without also needing a minimum 13 Wisdom to multiclass. I think the first level pays off better than the second, with the dark vision and initiative advantage.
The second level mainly just adds the channel divinity. Nothing in the text of the ability says it magically mutes light down to dim, just that it creates dim light within a 30 foot sphere. I think most tables are going to assume light works in a rough approximation of its normal, real world, additive manner, such that adding dim light to bright light does not create a dim light condition for Shadow Blade. If it did there would presumably be language about it keeping out nonmagical light as there are in certain other spells and effects. Even if you get a ruling in your favor, a Bladesinger already has lots of action to activate buffing options. At some point you have to start using your actions to swing that weapon.