The best factions at the moment do not need Heatwave because they are overtuned. Heatwave would break devotion for both SK and NR meta decks, both of which currently dominate. They don't use scenarios because they don't need to, so this comment is ignoring some significant factors. I don't think scenarios should even be a thing frankly but some have to rely on them while others don't which only highlights the glaring issues with the game.Am just a beginner (MO) so may not have my facts right, apologies if so.
Re Heatwave and 'It's very frustrating to see this card in every single match at higher ranks/pro rank. '
Looking at a couple of meta websites, the top 2/3 decks do not play a scenario or Heatwave, for whatever reason, so it's possible to create the best version of a faction deck without them.
If the best deck from each faction was running them, then that would suggest scenario should be reined in, and each faction should rely more on their best mechanics, rather than a general one.
Even at my rank it's frustrating coming across Haunt and Heatwave, say.
If you can't remove the scenario you may have a chance of removing a spawned card later, but that probably still leaves 10+ points on the board.
Sounds like a scenario should have a lower total output and provisions to match. i.e. to make it less of a points swing.