Percentage Based Lists
The idea behind this one is that, like in fantasy, you can only spend X% of your total points on the various unit types and must spend a minimum on others. Personally I can't see this coming into effect, but what I can see happening is Allies and/or Super Heavies only being allowed to use up 25% of your total points (Knights as Primary Detachments being the exception, but if you're playing that then you're a douche anyway). This won't have a massive effect for some people but it keeps Super Heavies out of small points games (the 375 point Knight is exactly 25% of 1500) which is a good thing and it also means that you can't just take a super tough/killy HQ and 2 bog standard troops and have your "allies" making up the rest of your army. I admit I've used Smashy, a Tactical squad and a Scout Squad as a Primary with the rest of the list made up of the Imperial Guard I actually wanted simply so that Slay the Warlord wasn't such a give away.
This is a new one, and I'm on the fence about it. Basically what happens is you write out 75% of your list. You then write out 2 versions of the other 25%, Sideboards A and B. Then you may look at your opponents "locked in" 75% list and decide which Sideboard you wish to take. In a 1500 point list, for example, I could write out 1125 points of a Guard list. Then I'd write out my Sideboards like this:
A: 1x Melta Cannon Imperial Knight (375) - 375
B: 3x Hydra's (210), Vet Squad (Chimera, Heavy Flamer, 2x Flamers, Carapace Armour, Vox Caster) (165) - 375
If I see they have taken a fair few flyers or skimmers I can then take Sideboard B for another scoring unit and a decent amount of AA, otherwise I would choose Sideboard A as it is more damaging against general targets and especially vehicles.
This would be a good idea for making all comers lists and help to deal with deathstar units as you could put a counter in and then simply not use it if they don't take it. The problem though is that it's similar to list tailoring. You can see what they're taking and be able to take a hard counter. Blasts in 1, AA in the other. You can now deal with Hordes or Plane spam. Like I said I'm on the fence with this one, it's useful but borderline cheating.
Consolidate/Sweep into another Combat
Not liking this one. It would be too powerful against gunline armies. In a single turn one hard-hitting uber unit could take on 1 unit in the gunline in combat, beat the crap out of them then move onto the next unit wiping most of their army out in 1 turn. Even if you could Overwatch each time it'd still not be enough unless you are Tau and even then it'll still be devastating.
They are the big ones at the minute. Not looking too great but it has potential. By the way the pic came from GW Liverpool (NSW)'s facebook page and 40k rulebooks are no longer available so something big is certainly on the way.