I'm more annoyed that they don't bother to go back and retool some cards that are completely forgotten. I'm talking about cards that have been in the game from the beginning or the first expansions, not like GvG cards that got left behind by shifting metas.
Blizzard doesn't want to buff cards. There was this whole dialogue between Kripp (proponent of buffing old cards) and Ben Brode over it.
The gist of Blizzard's response was:
*Some cards are bad because they serve as teaching tool for new players to figure out which cards are good vs which cards are bad. It's an acquired skill to figure this out and a player journey as they say. Eye for an Eye was given as an example.
*Some cards are bad now but may become good later one with new cards. Stuff like Wisp being playable because of Hobgoblin (or other 1 attack minions).
*Buffing old cards is confusing for new players who don't play every day and may come back after a while. Like they stated that casual players would come back to the game after a long break and realize a lot of their cards are changed which is frustrating for them.
*They don't want to constantly buff cards because buffing cards changes up the meta and thus there would never be a phase where players are refining/perfecting their deck play. That period is important in game development for Blizzard.
*Buffing cards still takes a lot of work because even though you don't need to come up with new assets you still have to playtest them in numerous games in numerous situations.
*Some cards that are perceived as bad may in fact be good or vice versa. Perception of cards change over time as well.
*They would just rather make new cards than buff old cards.
*They stated that not every card can be good and there will always be bad cards because of power level creep (like Yeti used to be good, now it's mediocre because of Shredder). Though Kripp already admitted to this numerous times so I don't why this reason is always brought up.
Of course this doesn't cover the Tavern Brawl or Arena reasoning because at that time Tavern Brawl wasn't announced yet.