Okay, so I'm going to post a series of guesses here on what I think will *possibly* happen with the new weapon stats. I'm doing this based on nothing but the preexisting weapon stats we already know (Bolter, Flamer, Lascannon) and what I think would mirror the weapon's intended purpose. I'm curious to see, once the edition is released, how right or wrong I was. Feel free to play along: post your guesses and we'll see, in the end, who is the closest.
I'm going to focus just on Imperial weapons at the moment.
Lasgun: as is, AP 0, D 1
Multilaser: as is, AP -1, D d3
Heavy Bolter: as is, AP -2, D 1
Autocannon: as is, AP -2, D d3
Battlecannon: as is, Ordnance 2d6, AP -3, D d3
Demolisher Cannon: as is, Ordnance 2d6, AP -4, D d6
Plasma Gun: as is, AP -3, D 1
Plasma Cannon: as is, Heavy 1d6, AP -3, D d3
Krak Grenade (Thrown): as is, 8", AP -2, D d3
Frag Grenade (Thrown): as is, 8", Assault d6, AP 0, D 1
Krak Grenade (Launcher): as is, AP -2, D d3
Frag Grenade (Launcher): as is, Assault d6, AP 0, D 1
Krak Missile: 48", as is, AP -3, D d6
Frag Missile: 48", as is, Heavy d6, AP -1, D 1
Hunter-Killer Missile: as is, AP -3, D d6 (re-roll to wound)
Meltagun: as is, AP -4, D d6 (Re-roll to wound under half range)
Multimelta: as is, AP -4, D d6 (Re-roll to wound under half range)
Meltabombs: (Close Combat), Str 8, AP -4, D d6 (Re-roll to wound)
Heavy Flamer: 8", Assault d6, Str 5, AP -2, D 1 (Auto hit, ignores cover)
Grav Gun: as is, Rapid Fire 2, AP -3, D 1 (wounds on armor save)
Grav Cannon: as is, Rapid Fire 3, AP -3, D 1 (wounds on armor save)
Sniper Rifle: as is, Str 4, AP -1, D d3 (+1 to hit)
Some notes on rationale:
I think blast weapons might (and probably should) simply work under the assumption that you get a random number of shots and then roll to hit as normal. The 1D6 for small blasts and 2D6 for large blasts should pretty much even out to the kind of damage these weapons usually do anyway (1-2 hits for smalls, 3-5 hits for larges) with occasionally swings in luck.
I also think we might see the end of Salvo weapons. I only say this because I found the rules for them needlessly fiddly. More likely just make them Rapid Fire with a number attached. Double shots under half range, regular shots otherwise. I wouldn't be that surprised if Grav Amps went away, too.
Anyway, those are my guesses thus far.
Minor edits made - Iris.