It isn't bad. I prefer using my ES to level my wolf with, over my SE despite lacking a lot of buffs in comparison. With the summoner, I like that I don't have to change target to the wolf to heal it, but I waste a lot of MP using servitor heals, since I heal for more than the wolf has HP :p But the summoner is over 30 levels higher than the wolf, so it's more efficient if the level gap isn't so huge. More so in CT1, with the level penalty and all.