Let's start with Movement. Each unit has a movement stat and does actually change depending on the unit. They did mention that Eldar will move faster than a Guardsman but Hormagaunts will move faster than Eldar. It was not mentioned how running takes into effect, but if I had to speculate (and this is just speculation) that it would be a simple D6 roll instead of shooting like normal. One thing to mention is that it will make things like transports more viable especially if their base movement is twice that of standard infantry. I'm liking how each unit moves a bit differently than each other and makes certain choices more viable depending on the situation. It even makes the different races and factions have more personality and different tactics simply by changing the movement statistic. Terminators are a bit slower than Space Marines, but not by much.
Weapon Skill is now just a straight number to hit just like Ballistic Skill for shooting. No more chart comparisons. This will lower the barrier of entry for people just starting back into the game. It always has been a set number but now it is no longer confusing for newer players to figure out for close combat. Another welcome change to the game as it will make the barrier to entry that much easier for people.
Strength and Toughness are still in the same way you expect. However, they have mentioned that weapons no longer have a drop off. For example, if you fire a Bolter at a Ctan, you can still wound it on a 6. The reason for this is because you will see Strength, Toughness, and Wounds go above 10. It was annoying in previous editions to look down at the table and realize that 90% of my weapons couldn't hurt a model that was put on the table simply because of how tough it was or because of its armor value. Now, you at least have a chance to dent it whereas before you didn't even get a chance to try.
Wounds work the same way. However, you will see models go above 10 wounds. This may seem a bit overpowered now, but as you'll see with the weapons later on, that isn't going to be too big of a factor.
Attacks are... well... close combat attacks the model can make each close combat round. The only thing I have to ask is whether or not bonuses to attacks are still applied. For example, if I take a bolt pistol and a chainsword, do I still get a bonus to the Attack value?
No mention about Leadership and how moral will work in this edition as of the time writing this. Strange.
You'll also notice a distinct lack of an Initiative stat. Nothing has been mentioned about this, but I would guess that this is because close combat attacks are done depending on who's turn it is ala Age of Sigmar. If you charge in, you go first.
So how do vehicles work? Well, they answered that with the Dreadnought.
Vehicles now have wounds like a unit. Another thing that was mentioned in the Live FAQ is that vehicles and monsters will get weaker as they take wounds. I would imagine that this would be similar to how Age of Sigmar does their giant monsters and characters.
Armor values are going the way of the dodo. Good riddance! The Armor value system either made it so that vehicles were way too powerful or way too easy to kill in previous editions. The invention of Hull Points helped balance this out somewhat, but it was still a problem that had to be ironed out as the Hull Points seemed too few and far between at times.
You may be scratching your head going "How is a Lascannon gonna deal with that?!" Well...
Let's start with the Lascannon. You may have noticed a few things have changed with AP being a negative number. Instead of being a "Yes/No" save system, they modified the save depending on the weapon that you fire with. In the case of the Lascannon, its -3. Which means the Dreadnought (or a Space Marine for that matter) has a chance to save against a Lascannon on a 6+! Where before, they didn't even get that chance aside from cover. How cover will play in the new rules system is yet to be determined.
Damage is done on the model hit, not the unit hit. So you won't be seeing Lascannons shredding multiple Marines should they fail the save like in Age of Sigmar. The Flamer, on the other hand, has multiple attacks that automatically hit. They mentioned specifically that Burna Boyz are going to be pretty powerful this edition.
Templates are going the way of the dodo as well.
D Weapons are also going away, as the Strength is going to go past 10.
Personally, I'm really REALLY liking these changes announced so far. They simplified the game, streamlined the model's statistics, and made the weapons a bit more viable. The only two things that concerns me now is how cover will play a role in the upcoming edition and how Overwatch will work. If it remains the same, then I have a feeling all of this is going to be pointless. However, I doubt that it will. If I had to speculate, I would imagine that cover would just give a bonus to your save depending on the type of cover you are in. Say if you are in woods, then you get a +1 bonus to your save or a bunker is +2 up to a maximum of 2+. I would also imagine Overwatch is either getting reworked so that you forfeit your shooting to shoot the enemy should they charge you or scrapped all together.
Well, that's it for now. I would imagine more information will be released as the edition comes into the fold.