It depends on how you assess potential, IMO. Ward has dominated every level he has ever played at. Every single one. Take a look at his stats from the WHL and the AHL during last season. He was twice the WHL's goaltender of the year and was the MVP of the WHL in his final season. He was named the CHL's best goaltender that year as well. Many claimed that his numbers were so good in the WHL because of Phaneuf and Woywitka, but they were proven wrong in his first pro season. He went into the AHL last year and recorded 6 shutouts while maintaining a 1.99 GAA and .937 save percentage. All of that as a rookie goaltender in his first pro season. Toivonen didn't even replicate those numbers in his second year in the AHL, which was the lockout season. Again, I don't want to be misconstrued as a Toivonen basher, because he's an outstanding young goaltender.
It's a mystery to me how one can judge potential anyways. Ward has had games where he has looked like a franchise caliber goaltender and so has Toivonen. They have both been fairly inconsistant, as young goaltenders are, but I think the differance is negligible to say the least. They were both drafted in the first round of the 2002 Draft, and neither has done anything to hurt their stock. They are still as close as the draft selections would indicate, and I feel that Ward is just a hair better at this point. Granted, Ward's numbers haven't been great recently but that will be a passing thing. We shouldn't jump so quick to judgement based upon 20 respective NHL games for both men. If that was the criteria, then they would all be behind Ray Emery.
It must also be stressed that the differance between #12 and #17 on these lists are very marginal. There is so much young talent coming into the NHL right now, that those rankings can be just downright personal preference and one person to the next might tell you differant things about both players. I just get upset at people who give the edge in "potential", which is a very liquid asset, to the player that is more mysterious and more unknown. Kari Lehtonen had this same luxary over Marc-Andre Fleury, and it was just as annoying then as it is now. People always want to take the unknown quantity.