Interesting points you raise. I can't remember the last time I watched an orc mirror on TS. I would think that a fast tech isn't a good option because as you mentioned the traveling time to the opponent is vast (crossing either bridge etc.. takes ages) if you're going to harass. Also take into account how close the creep camps actually are, it's a super quick level 2 if done right and even a quick level 3. I guess a lot of top class players don't do a fast tech because they prefer to play it safe? Something to think about anyway!