Hey Grey Knight players, have you bought your StormRavens already? Good, because when you see the codex you're going to be mad.
They don't get the cool anti-tank missiles that the Blood Angels get. Instead you get S4, AP4, small blasts that cause Psykers an an extra wound. That's right, the GK StormRaven isn't intended to be an anti-tank platform. It's made to sort-of kill hoards. You know, the thing that GKs have all sorts of other tools for.
Ah, but what about the Dredknight? Well no, you get a Hellhound Inferno Cannon and a Leman Russ Punisher-ish gatling weapon. Or a S7 large blast gun. So you'd better be good at getting side and rear shots with it.
What's that leave for long range anti-tank work? Rifleman Dreadnoughts and Jokaero.
The Dred option isn't bad at all. You get a 5 point ammo option for +1S that gives you 4 twin-linked S8 shots with 2 twin-linked autocannons. But like Hive Guard, you're going to see these everywhere. Which will give the fluffiest "GKs hate being entombed in any place that's not Titan!" purist players absolute fits because they'll have to take them. Because they sure as Horus won't take their other option.
That other option is Jokaeros in Chimeras. These guys are mini-Obliterators that can fire as a Lascannon,
You're going to see them spammed all over the place for a while, but after the dust settles I expect you'll see them pared back to something like the following, sitting in the backfield:
171 - Henchmen w/2 Jokaero, 3 Warriors (Plasmas), Chimera (Hull Heavy Flamer)
With the range bonus (~41% chance), you'd have five 24" plasma guns firing on the move. Or 2 Lascannons/Plasma Cannons plus 3 Plasma Guns when sitting still. Not bad.
Now, the GKs do have quite a lot of good medium-range fire. If you can get your Psycannons within 24" of a target transport, it's toast. But those weapons are going to be on some very small elite squads that will fall quickly to melta fire. So having some guns in the backfield will, as always, be necessary in an all-comers list.