There are some good points there. Any “for the rest of the game” effect that cannot be removed “limits design space”. Brann limits design space for anything with battlecry, and Odyn limits design space for anything which grants armour.
So… either fix the problem with specific tech (ie battlecry: remove all “for the rest of the game effects”). Similar to what they did when they made Skulking Geist to counter a specific problem card. OR, nerf the problem cards so they create a removeable object which can then be removed (eg Rheastrazsa).
Of course, that brings me on to cards that remove such “permanents”. The only one I can think of right now is Reno. I’m OK with his effect doing one sided removal, but as I have said on here numerous times, I don’t like his one sided board lockdown. But that’s for another topic.
Back on topic: we would need a card(s) that can remove a “permanent” object from the board. We currently have Demolition Renovator, which removes locations, but it isn’t played, partly because locations aren’t permanent. If it could remove ANY permanent item, it might see play. Having said that, using tech to counter OP cards doesn’t give balanced gameplay… its the OP cards that are the problem.
It is possible to remove the portal created by Sargeras, but cards like Odyn and (new) Brann cannot be countered. Having said that, they are both very bad tempo plays, while playing Sargaras for his “rest of the game” effect at least gets you 2 3/4 taunts on the board that turn.
Also, all those cards are class cards, so they are only as good as the class they work with. However, two of them are for the same class, and while their effects don’t stack directly, you will get double value from cards that grant armour as a battlecry. Tidal Revenant becomes 10 face damage AND 16 ATK for 26 burst from hand. Lava Shark will dredge 2 cards, and grant Armour (and ATK) from both, and General Vezax will grant 8 ATK and can use its effect twice to clear big minions from the board and be revived both times from the Armour it generates.
Obviously Sif needs setup, but its not hard to do that. Malygos usually wasn’t too much of a problem unless it was cheated out, so you have to consider that mana cheating is the problem rather than the card itself.
Helya pretty much needs a dedicated deck, so its only ever going to be as good as the rest of the deck, so I think its OK. Also, now that ETC is a thing, it is much easier to add tech without giving up a normal deckslot. Tradeable cards also can help with tech… although they do use a deckslot each, they don’t become stuck in your hand.
1 mana magnetics granting windfury is a problem. Sure, you have to rely on RNG, but even so. Windfury probably shouldn’t be available for sparkbots.
Anyhoo… I also will be sad to see duels go. I hope it can be saved, or relaunched, but I suspect its a done deal