Youtube's biggest problem isn't having another competitor come in since that probably won't ever happen. They're biggest problem is slowly losing profitable niches to other services. The first big blow happened last year/this year with all the Vevo mess of them spinning everything off to their own website. Now I think were going to see a big chunk of the gaming audience move to green pastures and the rise of Blip or even twitch in this field.
Google doesn't know what to do with youtube, its pretty evident about this when we keep hearing murmurs of a youtube paid music service that does against google's own Play Music.
Twitch could really take a big chuck out of Google by the summer if they start too build their service around not just livestreaming, but regular youtube style uploads as well. The PlayStation 4 has twitch streaming built in, and Steam/Xbox one are getting it early next year.