The only thing it could possibly ruin is self-poison archetype, which, I agree, is a problem.
But otherwise, a 4p Fang applying a poison to a 5p body would result in 7 total value which is exactly what 4p cards play for currently, and have the additional benefit of taxing further boosts on that card, which is especially relevant against self-boosting engines. That's much more reasonable than 2 4p's easily playing for 16-25 value together. Over half of which is removal, which is more valuable than raw points.
In fact, it could be even stronger against them this way, because you get to partially control more targets.
Which, in turn, could make cards like Rot Tosser and spell-tutoring Blightmaker relevant. Maybe even Dames, who knows?
Well, currently it's "just removal". Unitless ST in particular pack so much removal, they have to discard it sometimes. And it automatically makes the vast majority of engines and soft control options obsolete, greatly limiting the variety of the decks. Not "counterable", but nearly or completely unplayable. Only NR currently can afford to play pure engine decks, and even then, only because of having a bunch of copying cards. You're entitled to your preferences, obviously, but it's definitely not a good gamestate.
Interactivity isn't a subjective thing. There's only one way an encounter between Emhyr and Heatwave can end - Emhyr dies. That's it. The only possible outcome, a 1 for 1 trade. If countering him required locks or several damage sources, and, conversely, actually using him required additional boosts and purify tech, that would objectively be more interactive. Again, you're entitled to your opinion, but I find tense contests of objectives far more enjoyable than 1 for 1 trades.
That's kinda true. Or, rather, it could be, but isn't, because when you start a game against any given metadeck you know what card you will have to Heatwave/Invo/Vilgefortz/whatever long before it appears on the board. There's no complexity to it, it's just pure formality. See pirates? Expect Crach. Playing against the Gift? Gotta have the last say and nuke Gord.
I won't deny that there are situations where you have to deviate from the obvious line, but they are few and far between, and are usually forced by a dire boardstate, which means it's not really a tactical choice.
Yeah, precisely, you have to add hard removal. You could, in theory, forego adding Invocation and Anseis and try to get even greedier, but in reality this won't get you anywhere, because the game is so oversaturated with easy and reliable hard control options, that even a ridiculously greedy deck often has trouble sticking anything. So it's much easier and more reliable to have Invocation than one additional greedy engine, because unlike, say, Emhyr, it's virtually guaranteed to find a decent trade.
