I'm wood-shedding, big time, for the rest of the year. Started this little intense practice project in late October last year. I'm averaging, easily, over 8 hours a day. I had several weeks that were more like 10 hrs a day (I'm talking about seven days a week). I try to divide time between reading notes on the staff, playing with very clean sound sometimes, and very heavily-amplified sound part of the time (to check for peripheral string noise, inaccurate attack, etc), taking fast riffs and slowing them way down, working on simple exercises to teach all the fingers to be able to hit notes squarely no matter what, learning new chords and inversions (new chords always take a while), staying religious about the down/up-stroke thing, and doing everything in reverse (in other words: up/down) ... etc.
You have to be careful, doing something like this. I had nasty carpal tunnel symptoms for two months. I took a few days "off", which meant playing only a couple hours on those days. I try to take a 10 or 15 minute break per hour, but that seldom happens, it's more like every two hours.
What to focus on is a real matter of opinion, but there are certain situations, regarding practice, that can affect all of us. We all want to sound "good' of course, and as silly as this may sound, what that can lead to is a lot of playing, over and over, of things we already "know." That's no way to advance. Another thing, guys will play, say, a two-octave scale with maybe a leading tone and a couple notes over the second octave root, and they'll be sort of fluffing a note here or there, but most of the scale will sound just fine. If you keep doing that, you actually are training your finger muscles to fluff certain notes. Your fingers only do what you train them to do, they don't "think" for themselves.
If you have patterns that have two notes on some strings and three notes on others, it's easy to have some articulation issues when you're doing rapid ascending & descending lines. A lot of guys will just brush it off, and when they're in a "live" playing situation they'll use speedy playing to cover little issues like that. It doesn't work that way. You have to listen, real hard while you're running your so-called warm-ups or scales. If you hear some sloppiness, don't repeat the whole scale or whatever, focus on the notes right around where the sloppiness or string-change is happening, and repeat that until it's correct, effortless and smooth, at very slow speeds.
If we don't deal with "problem areas" (certain string changes, notes played by a 'weaker' finger, inability to play the riff slow and clean, instead of speedy and distorted, etc) playing "live' might result in our "avoiding" certain notes and things ... but the whole reason to learn the entire instrument, and to be a 'serious' player (if that's what you're after), is so that in a live situation our fingers and hands are so comfortable and familiar with possibilities, they can reach and properly hit any note, at any time, based solely on what we hear and feel at any given time, and not based on what we think we've memorized or a 'confined, limited" version of the fretboard. That's the ballgame, right there ...
Use a metronome and stay in tune. Believe me, if you're "in tune" and "on time" you will be way ahead of a ton of guys. If you're in tune and on time, simple can sound dramatic, and "fancy" is just gravy.
I've heard guys say, "It's easier to play certain riffs fast." That is total BS. What they're really saying is, "It's easier to ignore bs sloppiness when it goes by quickly." Meanwhile, their fingers are getting very very good at playing sloppy. That crap will come back to haunt you, trust me. The more you "practice" your mistakes, the harder it is to "undo" that muscle memory and then reprogram your fingers to do it right.
Guitar playing is fun, or at least it should be, whether you want to be the next Satriani or just a guy who can strum a few chords. It's all good, it's all valid ... music is a personal thing. it's your "voice", so you say what you want to say, the way you want to say it. All that is fun, for sure. But focusing on our weak spots, and being relentless about turning the impossible into the possible, then from "possible" to the difficult, from difficult into "okay when I'm 'on'" into ... effortless ... that is NOT always a lot of fun.
BUT, once you see some of the impossible stuff flying off the fretboard effortlessly, you just might see the hard "work" involved as a deeper kind of "fun." And if not, well, there's always the flute.