The pets do scale better once you get their "greater" versions. I can't remember how many pts you need to throw into the soul to get the greater elementals (elementalist) or greater skeletons (necromancer) but, I like many just for leveling purposes in early Alpha grabbed elementalist just for the pet.
Warlock/Elementalist use to be very very overpowered when I leveled. The talent you get in the warlock tree called "Mortality" use to have no cd and with all the buffs as long as the buffed lightning strike talents I could practically 2 shot regular mobs my level. Mortality with no cd made aoe grinding so ridiculously easy, dot an entire rift stage while tossing around instant lightning strikes (due to opportunity) and then use mortality when they got in range -> win!
I use to play it all the time at the end of Wrath and started to slow down when I got into Cataclysm beta so I could work on my mod but, I've been thinking about playing it again since wow currently is pretty boring with the lack of things to do.