Moonfall does not need to be a damaging spell.

Swapping Moonfall with Lunar rush? Yeah that was a good call.

That's about as far as the good ideas go here.

Diana had a lot of problems, but "not enough damage" wasn't one of them.

She was already a champion who could 100-0 you in a blink of an eye, and y'all decided to add several hundred damage to her only non damaging spell.

You want to make Moonfall strong enough to warrant Ultimate state? Fine.

You could...

• Give it cast range and make its location independent of Diana, letting Diana pull people towards a target location rather than just towards herself.
• Give it cast range but keep it on Diana, allowing Diana to blink a short distance before the pull happens (like Akali's old Shroud Blink).
• Increase the airborne duration, giving Diana a real hard CC ability.
• Make it slow attack speed
• Give it a 1 second silence
• Increase the radius
• Literally keep it the same as old Moonfall, same CD and everything, and let the changes to the rest of her kit shine

Just for the love of god don't give DIANA of all champions more damage.