A friend has an Ericson 33 that originally had a wheel and is now tiller steered. This boat's rudder stock has a top bushing and exposed shaft nearly at deck level so attaching the tiller was a simple matter.
He does have a circular hump in the cockpit where the original pedestal hole has been covered with a gasketed plate, but generally it's not in the way of anything while sailing. The original quadrant is still on the stock below decks, but again not really in the way of anything.
Wheel-to-tiller will obviously be less costly than going the other way, esp if you can sell the pedestal later on.
I have been crewing part time on an E-33 with the optional wheel for a couple decades. At one point we even had two of these rare Ron Holland-designed Ericsons in our little yacht club, and the second one had the stock tiller.
When we were shopping we really wanted to find an O-34 with the tiller, but could only find one with the wheel. We learned to live with the limitations, and there are times when the wheel has an advantage - like maneuvering under power in the moorage. For sailing it would be nicer to be able to sit on the combing with hiking stick in hand, tho.