It seems very strange to me in that mostly, it seems like the good units got better, and the bad got worse. Well, maybe not so extreme as that, but for instance, guardian jet bikes were awesome before, and now they're way, way cheaper, and the guns are even a little better. No one was taking banshees, mostly because they were expensive, fragile, and there was no safe way to deliver them....now they're still all those things, and they forgot their plasma grenades.
Guardians got pretty decent, to the point that there's no longer much need for dire avengers.
Both swooping hawks and warps spiders pretty good now, but I think it will be awhile before people realize that. Also, I think the warp spiders models are old and people don't like them. People who would play swooping hawks probably already have the models. I guess don't expect a lot of model sales.
All Bikes are good. Stupid good. Wave serpents and fire prisims are pretty good, but I hear there's not much point to the flacon anymore, which is weird.
I DON'T think the wraith knight is very good, game mechanically. Expensive as hell, but doesn't really give you any benefit over taking say, two wraithlords. The big problem is it can only shoot two guns(you can give it up to 4), and it's 3+ save. It also doesn't have a invo save. You can buy it one, and that's only 10pts, but it replaces it's two (really fancy) guns, meaning you essentially have to pay for two replacement guns, that aren't as good. To give you an idea, I think killing a riptide is actually harder to kill, and the riptide will come out at least 50 pts cheaper, and probably do more dmg (granted, with markerlight support).
Lots of people seems to like the wriathknight model (I don't, it's too big to be convenient to transport, and it's ironically too humanoid for me, much more so than the wraithlords or guard). But it's also $115, and people will start to realize it's not good in-game, and the novelty will die off. So you may be selling them now, but I wouldn't expect that to continue.
Wraithguard are pretty awesome, wraithblades look cool, but perform less well I think. Wraithlords are proabably a little better than before. Because they don't get stupid 1/6 without a chaperone and their guns are cheaper.
Banshees are awful. Scorpions are pretty good, but the game isn't so much about CC anymore. Shinings spears are awesome like all the bikes.
There's no real reason to take a vyper or war-walker.
Avatar is overpriced and I don't think there's a compelling reason to take him.
I don't love either of the Flyers game mechanically because they're expensive and fragile (AV10) but at least they have a hellacious output of damage. They're "over-balanced" like the DA and Tau Flyers. But at least they do look cool and they definitely have a use so I'd expect to sell them.
Since you need model predictions, Chase, I'd stock:
1) Guardians
2) bikes
3) Wraithguard
4) Farseers/spirits seers etc
5) the Flyers
6) I'd expect Wraithlord sales to pick up as Wraithknight sales taper off.