I don't believe that this change in the inclusion rate will have any impact on actual real investment spending by Canadian businesses. Businesses don't buy machinery in order to try to sell it later at a profit. That's where the capital gains issue would be most relevant. For running and maintaining a profitable business, this change will have no impact.
In terms of professionals, there are huge advantages, and not just tax advantages but also issues about protecting liability for the professionals involved. If they decide those advantages are no longer relevant, then they can organize their businesses differently, but I doubt that very many will do that. They'll still continue to access those benefits of incorporation.