I started to make a lock alt w' a friend and from whenever you can get the glyph slot to have DA available its fastest for some time. Probably till destro gets its ember consumers at the very least. DA being able to mass pull with corruption and ToC/slash x3 + 2x HoG charges is actually quite a bit of damage with 0 casting. Its the lack of casting that makes it quicker when we don't have tons of haste and there is lots of movement needed to level grind. Demonic leap also helps out in terms of mobility early on. Granted the last time I did it harvest life was still aoe but it should work well enough as it is now too.

Does it teach someone how to play the class? Not really. Then again you can half arse it to 90 pretty easily these days and again in LFR so I'm not sure when the education really comes in other than lots of experience and gradually going up the progression ladder. Possibly proving grounds though they aren't something that exactly jump out at new players either.