Yikes! She casts Ponder? As a repeatable ability? You know that casting Brainstorm every turn was the best bit about Jace, the Mind Sculptor, right?

If I increase the activation cost to either or , will that make it better?

Probably no. Alex and I had a discussion about this previously, and settled on Jushi Apprentice as being the go-to for powerful, tournament level, on the table continuous draw engine creatures. Sure, this card costs more in the front, but will cost you 7 mana in four turns to Ponder 3 times. Compare to Jushi which will cost 11 mana to draw three cards, and was still featured in every blue control deck during most of its stay in standard. Ponder every turn, at minimum, should cost three or four mana.

I know there's a good counter argument with Honden of Seeing Winds, so I'll make it to counter myself right now. Still, it seems to me that the easiest way to make this a 'fair' card it to either decrease the initial casting cost, and increase the activation cost, or to increase the cost to something like and let it be a 4/4 or so.

Would making it a Spellshaper make it any better?
, , Discard a card: Ponder
That way she really is 'casting' it every turn.

I do like the feel of discarding cards for the ability. I can't make it much bigger, because that would take it out of humanoid range. If I changed both its mana cost and activation cost to ? Or, what if it Pondered but didn't draw the card?

Ponder for 3 mana a turn is probably printable, but only at rare. Ponder without the card draw is much saner, and could happily be a 1 mana activated ability on an uncommon - similar to Sensei's Divining Top. Discarding to cast a full Ponder would also be okay - it'd be like Spellshaping it.