When you hear clear evidence that your practice is paying off it WILL cease to be a chore. Meantime, don't bore yourself with it 'cause you'll develop an aversion to practice and spend long periods of time not practicing followed by impossibly long boring routines which you only do out of a sense of duty and not 'cause it's fun. Little and often is best. Practice what's hard for you, the steeper the learning curve the faster your ascent.
It took me 3 years to start shredding, after the fourth I could play Midnight by Satriani (I learned from tab). AFter 5 years I started practicing sweep picking and wished I'd tried earlier, it's great fun. There are some cool sweep picking postings on this site, check out (for instance) Leandro Spataro (not sure on the last name) and Anthony Layne's postings on this.
I recommend you work on a few different sweeps at the same time. Try them at different paces, it's a surprising fact that (having learned a sweep at interstellar speeds) it can be harder to play it slowly.
Practically anyone can shred if they're dedicated, I'm not Mr Coordination but I CAN shred like a mother so keep practicing.
If you find any more cool sweeps on this site let me know!