This is a creature that I think fits white's flavor pretty well. White now is supposed to have the best fliers, so basically this is an instant speed Phantom Monster/Diving Griffin for 2WW, which makes it acceptable for white to play in a control deck. But its universal Ghost Warden ability makes it also powerful in a deck with a lot of white creatures, making combat hard for your opponent. So it attempts to be an all-around creature that you could play in many decks.
It is an instant speed 2WW Phantom Monster with a good ability, which is slightly too good in my opinion. I think the Vigilance should be dropped; it could still block as a 3/3 and be pumped by other creature, so it would remain playable.
This has a lot of abilities. I think you should drop the instant-speed, which isn't very white.
White has a lot of instant-speed pump- and protection enchantments. This is a pump effect and an istant blocker, somethinh that white can have at instant speed, and which makes total sense on this card.