Ok, so do you envision yourself as a great guitar player who can play all styles, or is there a particular style of guitar playing that you're wanting to work towards? Think of all the styles of guitar out there... rock, blues, jazz, country, classical, folk, etc, and then all the sub-styles of play within those... pretty much an impossible task to master them all... so can you narrow it down a bit? Are there areas that you have a lot of interest in, others that you have no interest in at all (at least for now)?

Do you see yourself being in an original band, a cover band, being a studio musician, a session player for hire, a solo artist or.... ?

If you could play any type of music right now, what would it be? What would you do with your developed skill set if you had it at your finger tips right now?

Do you have some guitar heroes that you look up to? People that are a role model for the type of guitar player you want to be?

Answering these questions (and I'd love to hear your answers) should really help you define where you want to go with your guitar playing. Learning other people's songs is just one way to improve, and not necessarily the best way for everyone. Steve Vai didn't bother with learning other people's songs when he was learning guitar. He also has some pretty insightful ideas about learning guitar if you search around on YouTube for videos where he talks about it.

Once you can give a tighter definition of your goals, I can probably offer some more practical advice that may help. For instance, if you miss improvising, and loved making up your own solos (but are not doing it right now because you're focused on learning other people's songs) then I'd say quit focusing on other people's songs and get back to improvising... there's some really specific advice I'd give on how to do that, but I'd like to hear back from you first so that I know that the advice I'm giving is relative to your needs.