If you think about it, the 2 pets for taos/wizzies r different. The taos pets are one of his main arsenal. And he summons them, they r completely reliant on their masters wishes. Wizzies pets are more of a luxury/commodity - espeically in later levels. Most wizzies I see leveling don't actually use them. But tamed pets are a 'wild animal' that you have seduced to work for you. As such, it will keep the mobs AI.
I agree with this though tbh - can you imagine a wizzie with 5 blue (or even yellow) frogs than can hit u from the other side of the screen. Wizzies would be dammed near godlike in 1v1 situations, and pretty fkin tough in mass pvp.
/Mark