Assuming there's a reasonable condi component, I can see Radiance being an important complimentary trait line. Condi-based retal would be nice. Carrion is an interesting idea, but I'm also interested in Celestial and Sinister. Guess we'll know more tomorrow.
I worked up a whole post on such a list last week but deleted it in my frustration of trying to complete the equation of (current profession) + (skill type from another profession) = (elite specialization). But now that we've seen dragonhunter, that equation seems to be accurate and the rumors of banshee sound like inside info. So let's see where we stand with the equations; perhaps we can complete them together.
Ranger + ??? = Druid
Mesmer + Wells = Chronomancer
Guardian + Traps = Dragonhunter
Necromancer + Shouts = Banshee (rumored)
Engineer + ??? = ???
Elementalist + ??? = ???
Thief + ??? = ???
Warrior + ??? = ???
I'll put forth three guesses. The first is Elementalist + Venoms, and the venoms will be elemental themed, possibly having interactions with attunements. The second is that thief or warrior will be getting some type of summon/conjure/pet/spirit/turret with their elite specialization. And perhaps Rangers + Elixirs = Druid?
I'm projecting what onto what?
So they've acknowledged a new design philosophy of making grandmaster traits truly necessary. I have no problem with that in principle. But I can't help but point out the irony that they're moving multiple traits to become grandmasters based on how useful players proved them to be, and yet we should ignore the reduction in build diversity because Anet has balance under control?