Specifically what is important to understand here is the fact that he is coming back into Standard for the first time since October of 2010. The game has certainly changed a bit since that rotation, as that was the beginning of the Mirrodin block, and Jace the Mind Sculptor's hey-day. How good is Nicol Bolas, Planeswalker today?
First of all, he's an eight-drop. 4UBBR is not exactly a pretty mana requirement to cast, and it's not like you can cheat him into play somehow. But when he does hit the board, you have a planeswalker with 5 loyalty and 3 very good abilities. His +3 destroys any non-creature permanent on the board, a solid plus ability. His -2 is a Mind Control without the enchantment, which is very good. Finally, his ultimate ability, which costs 9 loyalty counters is absolutely devastating. It forces your opponent to discard 7 cards (which most often will mean their whole hand), sacrifice 7 permanent and lose 7 life. Talk about card advantage. If this lives until the third turn it's on the board, you have the game essentially won against most decks. He's well worth the mana investment if he goes ultimate, but most of the time, you're going to just mind control something or destroy a pesky non-creature card that's in your way to push for game.
He's a great control card. Do I see him really working in this Standard environment? I sort of doubt it, but I know someone will try. He's just too expensive, really, in anything outside of EDH. Still, he's an awesome card to own, and will still be well worth grabbing out of this set just for collector's purposes.