I had a play white/green spell quest, so I put together a Mono-white mid-rangeish deck from the bits and pieces I've got in my collection. Then I went 3-0 with it... lol
I call it Mono-White Mess.
Creatures (22)
1-drops4
Skymarcher Aspirant3
Sacred Cat1
Dauntless Bodyguard2-drops3
Adorned Pouncer1
Knight of Grace1
Adanto Vanguard1
Glory-Bound Initiate3-drops1
Danitha Capashen, Paragon1
Sunscourge Champion4-drops1
Shalai, Voice of Plenty5-drops2
Angel of Sanctions1
Crested Sunmare2
Regal CaracalSpells (14)
2-drops1
Baffling End1
Seal Away3-drops1
Gideon of the Trials2
Radiant Destiny2
Oketra's Monument2
Sandblast4-drops3
Cast Out1
Ixalan's Binding1
Settle the WreckageLand (24)
2
Shefet Dunes21
Plains1
Field of RuinOketra's monument and angel of sanctions were instrumental in my wins. I played against Mono-white procession tokens (got a perfect curve and heavy cat beat-down action, but he actually dropped a lyra and 2 processions on me and I still won. Ended the game with 80+ life), mono-blue winds deck (which is a deck I want to build myself. I managed to exile his bombs and winds and out race him) and finally merfolks (Had to exile all sorts of nasty stuff like hadana's climb, deeproot elite and kumena. He got me down to 3 life, but I clawed back with lifelink and finished him with flyers and he luckily he never drew the merfolk that taps all my blockers).
It's not like I'm expecting anyone to play this mess, but it seems like white actually has strong, versatile mid-range deck potential. Can't say how good it would be vs approach (probably not very) but it has plenty of lifegain for rdw and exile effects a-plenty for scarab god nonsense. Against approach you can always exile PWs and have plenty of 2/1 1-drops to do plenty of early damage...
Could be a deck...