I really think we are going to see a lot of evoultion of the abillites like we did in diablo 2. People start off making every build under the sun, and then they find out which ones work best for specific jobs. There will be specific build/charricter combos that will work best for soloing, there will be ones that work best for being in a group (and having differnt jobs) and there will be ones for PvP, which at this point looks like a very secondary feature of the game, as there is no reward system for it as of yet.
The fastest way to do anything in D2 and in D1 was to do it in a group. It helped to have a tank that enemies could beat on, with a lot of high damage AoE mages blasting away enemies. Since we have no information at all what the rest of the game will look like, its impossible to say that any of these builds will be viable for an endgame charricter. Right now, people are only able to beat part of act 1, and have no idea what kind of challanges they will face later. This can lead to a lot of false strong builds. For example, in D2, I remember a necromancer was great in act 1 if you put lots of points into skellitions. You could summon a large amount of them, they (as a small army) would do pretty well, and you could have a curse or buff to help you finish off enemies. However, when starting act 2, such a build was completely useless as skellitions, no matter how strong they got, could just not hold up against the tougher enemies. I was able to beat the game with a sorc, barb, amazon, pally, but never a necromancer. I just found that there was not any specific great build for him, and just lost intrest in playing.
You have to keep all this in mind, and really be open minded about how hidden combos can work together, and finding new synergy between things could work.