I like an into and an utro, but saying that, if its more than a few seconds (the intro) then I get a little bit like 'Okay, we get it.. On with the video?' so.. making an effective intro in that time proves tricky for me haha, since I wouldn't put something in my videos if I wouldn't like it in someone elses channel! At the moment I have a little close up video I took of some purple lights as my intro with the title of the video there... Not great, but I'm workin' on it...
For the outro, honestly, it can be as long as you want it to be, I think the most effective outros are a background with a video or two on there, along with the channel name and your snapchat, Instagram, Twitter names ect (like Twitter:
@AmberAndGolden ect).. maybe with an animation at the start of the outro
But yeah! Convoluted paragraph there but..
TLDR: Yes, short intros are good, outros are also good lol