Overwhelming Hunger is likely to enable deathwish to be playable, there is also the MO scenario almost noone uses, which could support such a playstyle and with the new ability tying them together I would not be surprised if we would see a Tier 2-3 deathwish deck using it.
I doubt they will do anything about Arachas Swarm (as one usually nerfs the top end of the ladder and not tthe middle or even the bottom).
SY will try the new leader ability and with the only playable SY archtype being Blindeyes, which all SY decks have to run, we will still only see 1 style of Syndicate (which is funny given that SY is the only faction in the game with horribly designed archtypes), so there will be basically 1 SY deck and only slight variations.
As always Fruits of Ysgith pressure will exist somewhere if the meta is not greedy, so it will probably be mediocre.
Northern Realms will probably get a boosting deck with the new leader ability, so there should boosting (Uprising), scenario (Mobilization) and Inspired Zeal.
People will start using Imposter and at some point realize it is among the weaker NG leader abilities, if not their worst.
Skellige will maybe see a little representation on the new Blaze of Glory ability, it is better than people give it credit for, however by no means stronger than Patricidal Fury or Second Wind.
The dwarf changes (apparently large enough that the only statement for ST is how many non-dwarves get changed) will decide whether Mahakam Forge will be top tier, given that I have a soft spot for dwarves (maybe my favourite archtype) I might be reading a bit too much into it, however Mahakam Forge appears like it could make dwarves playable again (unlike now, where dwarves are just a bad joke).
No ST deck will vanish and Dwarves will join (for how long will be decided by how solid they will be).
And that is basically all.
I expect the new abilities to at the very least spark new Tier 2-3 decks (maybe not Hidden Cache and Blaze of Glory) or be solid to playable alternatives.
I do not expect any of the new leaders to warp the meta at all (except maybe Hidden Cache, given that SY is already willing to run awful leader abilities, so Hidden Cache does not exactly have strong competition, although that does not necessarily mean it will be better).