1) Lack of focus. You're not connecting the beats to what you're playing (I would imagine). Try breaking up things you learn into bars rather than just each individual click. Also try to hear the other instruments when you're playing.
Also, when you 'slow it down', be sure to have short bursts of playing it faster than it was intended. For instance if I'm stuck on a difficult riff that's at 130 bpm, I'll drop it down to where I can play it perfect, then drop it another 20, so lets say those numbers are 110bpm and 90bpm respectively. I'll practice at 90bpm for ~30 minute bursts then jump it up by 40bpm (to 130bpm) for 5 minutes in between bursts. Once I'm comfortable and bored at 90bpm, I move up by 5 or 10 to, lets say, 100bpm. Practice that in ~30 minute bursts and then jump it up to 140bpm for 5 minutes in between bursts.
Also, the farther you break something down, the better you'll know it. Practicing one lick or one bar is far better than practicing 4 bars at once.
2) Than fix it! slow down that metronome until you're playing absolutely cleanly. If that means playing it at 50 bpm, then so be it. You'll thank yourself when it all cleans itself up. It might help to work through some exercises involving the techniques you're having trouble with.
3) Sorta. Practice can be repetitive when you're focusing on scales and technical exercises, but these can be the difference between a polished performance and sounding like ass. Learn to love your practice. That's the best advice I can give. Learning songs is equally important but relying on songs alone to teach technique can be a difficult task. It's much easier to improve technique and realize that that song you want to learn is much easier than you thought it was.
I find breaking it up to be my best tool. 10 minutes of Technique A, 10 minutes of Technique B, 10 minutes of Technique C, then go back to Technique A for 10 more minutes, repeat until you've got 30-60 minutes of each one :) Sounds a lot less boring and manageable, eh?
4) See above and stop making lofty goals for yourself! Don't say: "I wanna be this good in x amount of time". Say: "I wanna learn x. I'm going to spend y amount of time on it every day."
Different things take different people longer to learn.
Some recommended readings:
Effortless Mastery by Kenny Werner
Zen Guitar by Philip Toshio Sudo