As mentioned there are multiple classes with distinct strengths and weaknesses. While tech cards can be powerful in the right matchup, usually you often dilute your deck outside of perhaps the strongest 2-3 + a generic all rounder into ETC.
Often the current meta decks might literally need to be disrupted 2-4+ turns in a row otherwise they might just bank their cards and combo you next turn.
Or be held back for 1 turn, then kill you the second or third.
Ex: Spellgiant Rogue: [Deck of 0-1 mana spells, gameplan is to spam them to play 0 mana 8/8 giants, shadow/step loathneb/yogg for up to 3-5 mind controls/hysterias/spell blocks, and 14/14 to 28/28 edwins as current as turn 2-4]
Viable semi counter cards:
o 2/3 Watch post: (Slows with +1 mana tax)
,
o 3 mana 2/4 drake with cards cannot cost less than 2
,
o Ashen elemental 3 mana 2/4: Deal 2 dmg to a opponent for each card they draw for 1 turn
,
o Loathneb: 5 mana 5/5 All spells cost 5 more next turn
Mage counter cards:
o Counter: 3 mana counter your opponent's next minion
o Counterspell: 3 mana counter your opponent's next spell
o Iceblock: 3 mana become immune instead of dying.
o Frost nova: Freezes the board
o Solid Alibi: Reduce all dmg to 1
These all can easily face one problem, A deck ONLY full of tech cards without a win condition, might just stall it’s opponent for 1-4 turns, expire,
A: then have their opponent dump all their saved cards,
B: mind control all your minions 4 time in a row,
C: Make spells unplayable
D: Dump 5/5 + 8/8 + 8/8 + 28/28 worth of stats on turn 6 after being disrupted turns 3-5
E: Or be a Odyn warrior or Questline Druid who you moderately annoy by freezing their face 4 times in a row, then get hit in the face for 12-28/++ dmg.
A->D can happen all in One turn, especially if you try to stall a Spellgiant Rogue, E might be majorly annoyed and frozen 1-4 times in a row to stretch out a finish.
But you can’t freezelock them forever, (at least, i suppose, without water elemental from ± oasis allies sticking.)
Now, it is true that Warlock can tikatus/discard, Reno priest can often run everything generically good and run neutrals and cheap removal and tech cards generally very well.
The deck can be fun, but is often ludicriously expensive (10k-30k depending on version). Especially if you want a renathal version. (20k-40k dust)
Most of mage’s 2 Frequent top mage decks are often Secret mage/ Timewarp Quest mage
Secret mage can counter both Minion AND spell. But it’s exhausted by health/armor. Platebreaker in ETC could counter armor, but both Odyn/QL druid will just rearmor.
It’s frequently top 1k legend capable 90% of the time though.
This is the first time in several years i’ve seen it be bad ONCE in wild. (Even though it was buffed for no reason last patch)
Quest mage might be another option. While you might not be able to maindeck any cards, I think it can combo timewarp and frost novas and alibis and permanently remove your opponent’s turn from the game by comboing a out of deck/ETC Potion of illusion/Iceblock, with a 9 mana card that recasts all spells.
While technically not doing list of all the above. It’s pretty much able to Lock your opponent out of the game, and counter all plays/freeze boards/stalls.
But just like a two edged sword. If spellgiant rogue plays a shadowstepped loathneb + 18/18 edwin 2-4 turns in a row, gg. Tech cards are double sided, and while i’ve seen a couple quest mages reach the top 2k-0.5k brackets, i don’t really see them anywhere at top 100-500.