In the past couple of days GW has release more snippets for 8th ed. now, we have hard statlines for space marines, Guiliman, dreadnaughts, and even weapons. The two webpages are:
[URL="https://www.warhammer-community.com/2017/04/25/warhammer-40000-unit-profiles/"]https://www.warhammer-community.com/2017/04/25/warhammer-40000-unit-profiles/[/URL]
[URL="https://www.warhammer-community.com/2017/04/26/warhammer-40000-weaponsgw-homepage-post-4/"]https://www.warhammer-community.com/2017/04/26/warhammer-40000-weaponsgw-homepage-post-4/[/URL]

First thing is it looks like they have addressed the imbalances between vehicles and MCs. There is no longer a toughness vs AV to deal with, dreadnought, landraider, carnifex, wraithknight, they all use the same system, they only difference is the vehicles toughness and how many wounds it has. Lighter vehicles like dreadnoughts and hive tyrants will be T6-7 and have W6-8 whereas a heavy vehicle and MC like landraiders and carnifex can be T8-10 and have W12-16. Well done GW, this is actually a sensible solution.

The changes to weapons really bring 40k's core mechanics inline with AoS. We all know about the removal of template and making the flamer 8" assaultD6, and the change to AP system, instead of a binary save or no save we compare bonuses. I shoot my lascannon at you terminator, your terminator has a 2+ armor, my lascannon is AP3 so your save is now a 5+. But, your terminator wasn't a moron and was in cover, giving you a +1, it was a ruin, that's another +1, that ruin got the techmarine bolster defense, that's another +1. Roll me a 2+.

The big change to the games core is that weapons now have a damage stat, means that is a shot is unsaved, the weapon will deal more wounds to the same model, AoS players know this mechanic well. For example: If I shoot a lascannon at a hormagaunt, and the wound is unsaved, the lascannon deals one wound to the hormagaunt brood one hormagaunt is removed as a casualty, as normal.... the change comes when I shoot a carnifex with that lascannon, and the wound is unsaved, I then get to roll another D6 and remove than many wounds from the model. Which brings me back to the balance of vehicles and MCs, a dreadnought now have W8, meaning that even with a lascannon, a dreadnought can never be one shoted, you can get a lucky damage roll and two shot a dreadnought, but gone is the problem of a carnifex taking three lascannon shots while a leman russ gets blown up by one shot.

Oh huge change, where is that fairy to say "hey, listen"

The rules team behind the new game have taken the opportunity to rebalance a lot of the weapons in the game, and with the new armour modifier system and removal of the cap of 10 on Strength values, we’ve made sure that every weapon has its use on the battlefields of the 41st Millennium. D weapons, for example, are gone, and instead there is a scalable Strength and damage that matches the effectiveness you’d expect from every weapon.