Depending on the depth, fishing over it may be hazardous as springs can weaken the ice in those areas. The lake my family cabin property is on is spring fed and you need to be very careful when accessing until you get out over the first drop as there are springs along the shore than never fully freeze.
As for the fishing itself, I think overall structure of the lake might have a larger impact than where the spring is. If the lake is featureless, the spring might be enough of a “difference” to be a draw.