I still help players with class stuff to this day, as do many of my guildies. But I only help when its asked of me.
One of the best friends I made in WoD was a hunter I met in LFR, her dps as BM spec was much lower than mine despite being pretty close in gear. So after the wing was finished... out of the blue she whispers 'can u help me i don't know why my dps is so low don't know what I'm doing wrong'. So I invited her to group, looked through the logs for a couple bosses and quickly established some stuff: things like, she wasn't KCing on cooldown (less than a 3rd of my total KC casts) and also that she didn't always use Bestial Wrath.
So I helped her set up a couple of useful macros, stressed that KC was her nuke to always be pressed, and just gave her a general sense of the spec's priorities. Once she got used to doing the stuff we discussed and got some better-itermized gear (hers was lacking in Mastery), her dps shot up considerably.
The 'help' that people reject are the "excuse me i noticed that ur dps is really bad" tells out of nowhere. Give advice when you're asked for advice.