What was the rationale for the two point penalty in the off spec trees? You're already dumping points elsewhere. No skill tree based mmo I've played (WoW, Rift, SWTOR) does this. Spec too deep in one tree, the best stuff in other trees are already off limits to you so why the need for this increased penalty? It's already baked in.
Also, with regards to BB...I watched the video released a couple days ago, and it really didn't seem all that compelling. If you guys had to estimate, how much of the expansion content is BB? 30%? 40%? Is there still going to be mounted combat?
regarding the skill trees, it is because passive traits are gated to your depth in a skill tree. The intent of the trees as pointed out in the stuff Turbine put out was "hard choices". They want you go choose. Remember, you can switch trait lines out anytime if you are out of combat. However in combat you will find your generalist builds harder to do or even impossible.
what is going to be interesting is the creative "builds" folks come up with. You can get to the capstone of your tree with a fair amount of points still available at 85. Add 10 more levels (or over the course of another year or two - more levels) and you can add more. But it is a big change. My main is a cappy, definitely an adjustment. New challenges, new things. It really grew on me some. If that helps.
Regarding size of BB. I don't know how to answer that. The landscape is large and there is a lot of quests. BB are certainly a major part of the expansion. I found them only mildly interesting solo. However when I did them with some kinmates, I actually had a good time. But it is very different sort of gameplay.