As I recall, spell slots were not often a very big issue for me at lower levels, and I was playing a shaman. I'm not sure why that was, maybe it was just not grouping as much, never getting buff bots, and not having any clickies.
That being said, it would make it a lot less annoying to buff if you had combined stat buffs at a lower level. On the other hand, it would kind of take away one of the cool things about breaking in to the higher level game.