Coin needs to give more mana now, and be the option for sustain in the laning phase.
Currently, it's not viable and is outclassed by the other two options.
Increasing the mana gain would make Coin significantly more attractive without straight up busting it.
The ONLY advantage it has now is that it allows you to get to warding sooner.
Also, Losing the health or AP from the other support items essentially nullifies your impact in the early laning phase. If you don't have health, you can't sustain from harass, and if you dont have the AP, you can't really provide peel or harass.