The new Ajani planeswalker will probably not see much play beyond the sideboard in Standard and Modern. Nevertheless, mono-white Life Gain decks in EDH Commander can really make use of this card.
But even in EDH, it won't be used much as a Commander. It will act as more of a support card that can instantly wipe the board with his ultimate ability that surprisingly costs zero.
How will this affect the price? Most likely Ajani, Strength of the Pride will fall in price and settle at around $4 to $5 — or even less.