We accidentally connected 3.3V from our board to the transformer center tap instead of the suggested W5200_3V3A voltage. Will tis be a problem as long as it it clean power?
I do not think it is possible to tell you anything about consequences as have no idea about cleanness of the power, board layout and actual circuit. In general it should work the way you did it. And it is good question if it is better to leave this way or to rework.
That is our thoughts also. We will try to keep the voltage as clean as possible until we re-spin the boards.