I think it would be a staple in every standard deck just because they already play so many lands. The opportunity cost of a colorless mana source is pretty low. (Which is why we see Radiant Fountain in Control decks) So it probably would have to enter the battlefield tapped or have some kind of negative side effect.
Against a fast aggro deck, Radiant Fountain is probably more effective for getting you to the late game in order to cast your powerful spells. Drawing a card instead wouldn’t have the benefit of being immediately relevant.
In Vintage I think it would be good but it doesn’t immediately slot into Xerox or P.O. It doesn’t sacrifice itself so you can’t loop it with Crucible. Graveyard decks would wish it was “discard, draw” or vice versa.
And yeah Fantasy card thread. Thanks for the responses!