Solari is too strong

Let me get the item's active's stats for you real quick:

Grants a decaying shield to nearby allied champions and yourself for up to 2.5 seconds, absorbing up to 60 - 434 (based on highest level between target and caster) (+ 2% - 36% (based on level) of caster's bonus health) damage (90 second cooldown) (600 range).

The shield can get to a pretty decent size, but it is a decaying shield. It gets smaller over a short period of time and doesn't last too long. It is a good item to counter burst from the enemy but needs to be used at the right time and has a decent cooldown. It's also worth noting that like redemption, Lockets used in quick succession have reduced effectiveness. I personally think the item is just fine. ¯_(ツ)_/¯

EDIT: Forgot to mention, pretty sure the reason that the shield looks so big on an ADC is because they usually don't have a ton of health to begin with.