Enhancing Totems will be changing to provide an additional shaman-only buff when the buff totems are down. Technically that implementation is tricky so we just haven't finished it yet. In general you are correct that there should not be "buff my buff" talents. There are a few exceptions where a buff is elevated from a minor bonus to a more serious bonus (Elemental's spell power for instance).
Mental Quickness is something Enhancement and Retribution need in order to be a mana-using spec without mana on gear. In general you won't see stat conversion talents, though warriors and DKs might keep their armor conversions. We'll see.
We may need additional mana restore mechanics than we have now for Enhancement, but that will take some more testing.
We're not sure what we'll do with Ancestral Swiftness. We made that talent before you could wolf indoors, so it may be less attractive now.
The Searing Totem mechanic is obviously something new and will take some iteration.
Someone mentioned Imp Windfury Totem. I think you're looking at an old talent tree.
Enhance is intended as a dual-wield tree. We aren't going to support a competitive 2H spec. We aren't going to prohibit it, but it won't be competitive.
There are going to be some hard choices in all the trees. It's not our design intent that you scoop up every single talent in your tree
I personal buff for dropping a totem... I like that Indoor GW is nice. It would be a tough choice to me. 30% when in wolf form plus costs a GCD, or 15% all the time with Ancestral swiftness.