You are talking about the (sometimes inevitable) arms race that TCGs fall into… GoW is resilient to that happening as (1) things can be patched/balanced if they are broken or unfair and (2) the devs seem to be aware of this risk…
For the record, I don’t think anything is currently broken (meaning a game-busting exploit of a combo or spell) - but the Goblins are disproportionately strong for their rarity and have good synergy and bonuses, making them by far the best option for most players needing a competitive team…
Most games like this need commons and crap to make the good ones look good… this game has a pretty decent meta, with a wide range of usable troops… or used to, but it’s risking slipping away, and Goblins are a big part of that loss of variety issue right now… it will be (eventually) fixed…
Not true, many decent strategies still use heroes, and for lower level players your hero will often be amongst your best cards. I am level 750+ and use my hero all the time - admittedly only 3-4 of the weapons currently mixed into my teams. And heroes are due some love / catching up in the next patch.
That part you’ll be stuck with for a while, I fear… unless some nerfing is done soon (not likely to be anything major or anything too soon)… one day the other types will catch up and some variety come back into it… but I too am fighting (or skipping) Goblin teams at least half my battles for now… sigh…