I don't like 'professional' intros for letsplay channels. If your channel is for game advice, walkthroughs, and guides an intro will make it more official.
I have a gaming lets play channel and I do what most big gaming youtubers do like PewDiePie. Just greet your viewer, state your name, and say what game you're playing. All of that in a few seconds. I think it gives a good human quality to your content.
If you're doing letsplays the viewer first comes for the game a returning viewer is coming for YOU so you'd want to illustrate yourself to the best of your ability.
I find making the intro and outro are tedious because I have to record it separately, but in the end you get what you put into it!