Yes and no. Leveling, yes, that's generally true. After you get better gear, it starts to reverse that trend. While I was leveling 1-60, I had problems (and it was wow 1.x not 3.x) with more than 3 mobs and couldn't solo any elites. With ZG and MC gear it still was hard to take on larg groups and elites. When 2.x came out and leveling from 60-70 I could more easily handle larger groups and some elites. At 70 with just kara grade gear I could solo many world elite mobs. And now with 70-80 and 3.x talents and what-not; Groups are no problem and elites are hard but doable. With a little bit of pre nax gear I have a breeze of a time with larger groups and elites.