No, part of your dues every year goes into a capital fund that pays for renovations, there won't be a surcharge. There is the opportunity in the contract for a surcharge if the resort gets a lot of damage - when VB was hit with a hurricane there was some speculation that DVC would surcharge VB owners - they didn't however.
Someone did a wonderful calculation recently where they adjusted BWV dues for the availability of standard view rooms. Once adjusted, BWV came within spitting distance of BCV for dues. There is also an issue with how Disney allocates transportation costs among resorts - the upshot of that is that BWV owners pay slightly more per room for bus transportation than the other DVC resorts due to how bus costs are allocated out.
Our last room was the best maintained and least in need of renovation in six years of ownership. But, I would really encourage you to try a DVC stay before buying. Even in our "pristine" room, I don't feel like DVC rooms (at least at the Boardwalk, which is where we've always stayed) are equalvelent to the quality in the Deluxe rooms (in terms of furnishings and bedding, etc). The quality of the furniture at SSR is rumored to be much higher (I think they went with the Thomasville brand), but SSR as a resort holds little interest for me. DVC rooms simply get used more and harder than their hotel counterparts - occupancy is higher, DVCers cook in their rooms, DVCers probably spend more time in their rooms (i.e. at least we all seem to claim DVC changed our commando touring patterns and we use our rooms for more than showers and sleep).