Depends on what your objective is.
Very few wonders in the game, if any, speed up your victory times. Doesn't mean you shouldn't build them if you have fun doing so, but every extra wonder you build is pretty much guaranteed to delay your victory relative to using that production on other things. If you divert international trade routes to domestic trade routes, the delay is even greater, as now you're giving up science, culture, faith, and gold on top of the cost of the production itself.
Just in general, if your economy is built around producing things, instead of buying them, everything is going to take longer. Running domestic routes to get more production delays things even more. Again, doesn't mean you shouldn't do it. Growing big cities and building lots of wonders can be great fun, in and of itself!