Unless there's a bunch of unwritten changes on this patch, the balance notes leave much to be desired and after probably 15-20 games last night it feels like that is indeed the case.
Ad Mech Ark is still not worth its point in a 2v2 scenario, I don't know if it needs buffed PER SAY as I'm sure it can work in 1v1 lists but just because it's 2v2 I feel like BS picks should still be viable. 2v2 seems more in line with take as many cruisers as you can with 3+ escorts or lose.
Ad Mech in general are still pretty much just IN. Their perks are not that great, they don't have any innate ability that the IN don't get(like a Repair that heals or something), they have no unique weapons that the IN can't take and they even LOST Melta Torps for some reason to IN only.
I played a decent amount of Necrons last night as well, picking the Cairn in 2v2. This is even worse than Ad Mech, 1 BS 2 escorts(phew). But I roll with it knowing it's my choice. Now I will say that Starpulse was addressed and it isn't nearly as bad as it was(good job) and the armor changes do seem to make them tougher(also yay).
The DPS on Necrons is...lacking. For it's point costs it should probably be doing a little more at least, especially with it's relatively shorter ranged weapons and long CD(this needs to be shortened IMO) on it's only mobility skill.
DE were hardly addressed, they seem to be the same cancer they were in first beta. Eldar got buffed to make it even easier to use their front guns and remained untouched on their DPS. These factions cannot remain this way on live.
System Criticals are absolutely out of control. My Necron BS can't go into a fight vs 2-3 ships for more than 7 seconds without a system failure. It is nuts, absolutely nuts.
Random observation but I ran into a Tau BS(the manta ray style one I forget the name) and it absolutely DECIMATED my Cairn in close range. I saw 2 laser pulses go through my ship and lost like 40% of my HP bar. It was out of this world. Nerf? I don't know but holy shit did I not expect that.
I hope there's more balance addressed before launch, but I fear there will not be. I feel like this is just basically early start for pre-orders(although it will be wiped on launch, we still get to have fun earlier).