I don't think you'd have any particular problems with planting wisteria on a south-facing wall - after all, we don't get much in the way of strong southerly winds in the UK - mostly north-westerly here, and I'm not far from NW Wales. I think problems usually arise with those plants which have foliage all year round, & a south-facing wall might mean that any plant there would get damaged by winter sunlight on frosty leaves, which wouldn't be the case with wisteria - or roses, come to that!