Tri spec or Quad spec (druid) would be great! Gives you more feel of the class if you want to try out all their spec without spending gold to remove a spec. If Blizzard does want us to feel that freedom with our class, this is a way to start. Some may disagree/agree, but I feel like it'll help, for example i'll be using a druid for this. A group of people are doing a dungeon at level 100, heroic that is, and the tank leaves because of reasons, and you don't want to wait X amount of time, the druid (with dual spec) only has healing and dps. If Blizzard were to have the option to have access to specs without spending gold or going to the trainer and learn tank, the druid can just switch to tank and start going from there. Then you'll have a dps slot open to find someone, but those are fast to find and on top of that, you can continue with a healer, 2 dps and a tank. I'm not sure if people do this like I do, but I usually carry my other spec gears on me just in case situations like this were to happen. So... long story short, yes it'll be great if Blizzard were to give you the maximum spec for each class rather than dual spec.