I didn't know Baku had the standard card draw mechanic either. In that case, I definitely suggest buffing it in some way. In my opinion, Baku as it is now is usually worse than a 0/6/0 Beast + Illusion card with 6 attack and no other text. By comparison, Wolf Spirit (0/4/0 Beast + Illusion, 5 attack) would probably be a better card than Baku, even if it never gave +3 recruits. Druid might be a better card for comparison, since it has the same cost and a summoning effect, in exchange for 1 less cost. However, Druid's summoning effect has an excellent chance at a rare card (at least, when used for a Nature card), and its keywords fit well with both Restoration and Nature decks. Beast often won't be useful in decks that use Baku.
Note that these comparisons don't necessarily imply that Baku is bad, especially since Druid and Wolf Spirit are both excellent cards in decks that can use them. I would, however, still argue that it is inefficient and its text is often a drawback, which makes me hesitant to ever include it in a deck. There are much better Illusion commons, and Illusion decks generally don't need lots of common Illusions cards. Beast decks generally don't want to clutter their hands with mediocre non-beast cards.
On the other hand, changing Baku to standard summoning probabilities (1/3 common, 1/3 uncommon, 1/3 rare in this case) might make Baku too powerful. Summoning cards (especially common ones) in MArcomage are, in general, very strong and probably usually undercosted for their power (though that is another topic to discuss). The fact that its cost is gems, the primary resource of Illusion decks, should probably make Baku balanced in Illusion decks, but if it is too strong for decks that are not starved on gems, we might see it taken in many decks, regardless of their type, due to its relative strength and (sort-of) flexibility.