#1
although it is on the topic of playing fast..

ok..

say I cannot play fast and feel my problem is in my left hand/ and not knowing the scale well enough yet, and have learned an e natural minor scale.

lets use the d and g strings..

so im playing: D-5 7 9
G:5 7 9 or simular, maybe a phrase using those notes..whatever.

and i put it to a metronome, build it up some.. over a week. now i know the 6 notes very well, and can do it without thinking about it. it just happens, muscle memory and all, but it isnt any faster.. theres still a point where i can go no faster. and it isnt any faster than before.
supposivly accuracy is speed..

thats one thing im struggling with..
another thing festering in my mind is..

after I do get the 6 notes at a fast speed. will others come naturally? or will i have to drill that pattern as well?
if thats the case I can see my practices all turning into building speed on one phrase after another..endlessly..

ok so what I feel like I need are some licks in the e natural minor scale to drill on.. I dont want to be the fastest guitar player ever..
I would like to "shred" however.
and i would like to add some fast runs and stuff to my nice medium tempo melodic solo phrasing..

ugh...now im rambling..and not sure what im even trynig to get at anymore, take of this what you will...
#2
tl;dr - Want to play faster, plateauing at certain speeds and not making further progress.

For those that don't want to read.

Personally I make sudden jumps. I'll be on a plateau like you are for weeks and then one day I'll pick up my guitar and without any effort I can suddenly play much faster.

To answer your question about having to drill phrases independently, the more you practice and the better you get, the less effort each thing will take to play the way you want to. So as you begin to build speed in one thing the speed of other things will go up as well, although not necessarily as much as what your primary focus is. You should however at all times be focusing on playing cleanly. It does no good to play fast if you can't play clean.