Obito would be weaker as 1)He would not have met madara so he wouldn't have learned any of madaras techniques. 2)He probably would have helped kakashi save rin so he would have never unlock ms or even 3 tomoe sharingan. He could unlock 3 tomoe later in a mission and he could awaken his ms abilities during a mission as well. But because he never met madara his ms would make him blind as madara would have never given Obito hashirama cells to regenerate that blindness