I can't say there's a good state of game balance right now. Cheap swarm cards are very popular options for shutting down more elixir-heavy investments. While cards at the top tier of play regularly get nerfed, these troops have been in the background causing more problems than proportional to their elixir cost. At the same time direct damage units are also an issue by going straight for the tower if a defensive building is not placed in front of them. Meanwhile, there are troops at the bottom of the barrel that haven't been touched/have been buffed ineffectually. My 'general balance' changes look at a large sample of cards and re-balances them.

Some of the candidates for nerfs:
Direct damage troops (Hog Rider, Giant, Royal Giant, Balloon) - direct damage troops are consistently meta material because other win-conditions are too easy to distract. Troops like the Giant Skeleton and Sparky can deal very high damage with for a high risk, but these troops are harder to stop because they won't be pulled down by your defensive units. If you don't have a building, it's very hard to avoid taking damage against these players, in particular when backed up by an AoE unit. Due to their pervasiveness, they led to the rise of cheap swarms as a good counter.

Low-elixir swarms (Skeletons, Goblins, Minions) - these cards give a lot of value for their elixir cost, particularly in terms of DPS. These cards aren't always mainframe meta, but have been working behind the scenes to keep numerous other cards oppressed. Troops like P.E.K.K.A. are crying because no one is using them, and these cheap swarms are why. Why waste your time and effort trying to get a big, burly robot to the tower when you can simply thrown down the Giant or Hog Rider and get easier tower damage? They don't get distracted by these cheap swarm units and still give a lot of DPS per elixir. Other point-damage troops like the Prince are struggling because while they do high damage they quite simply are too easy to distract and kite around with these swarms.

Spells (Zap, The Log, Fireball, Graveyard, Goblin Barrel, Rocket, Lightning) - because of all the cheap swarms running around destroying people's tanks like termites on mahogany, many tank users carry guaranteed-damage spells for crowd control. This isn't bad in itself because it stops a large push being brought down so easily by cheap swarms. However, this makes area damage cards almost pointless. Why risk 5 elixir for a Wizard who can be swarmed by Goblins when you can just toss a Fireball at the same tower and win? This explains the low usage rates of splash troops, in particular the Bomber (who can't see acceptance no matter how many buff it is given), the Dark Prince (who never leaves his own side) and the Witch (who now one-shots Skeletons...in a tiny splash radius.)

The Goblin Barrel is an interesting one because it can be countered...by spells. For its low elixir cost it outputs an insane DPS and forces the user to play an AoE spell to avoid taking major damage, because the tower two-shots them. Each Goblin gets at least one hit, dealing 288 damage, then the remaining two chip away for little risk.

Low-elixir utility cards (Ice Spirit) - they only cost 1 elixir and are fairly easy to deal with, but unfortunately when not killed off give too much value for their cost. An Ice Spirit + Zap destroys an entire Minion Horde and when combined with the Musketeer is very powerful against offensive pushes. Either their overall effectiveness or elixir cost needs to be looked into.

Before we think about buffing the lesser cards, I think we should mark out the ones that are just too powerful and rein them in first. Here are some of my considerations:

Splash damage units (Bomber, Baby Dragon, Dark Prince, Ice Wizard, Valkyrie, Witch, Wizard) - they're good cards, but outclassed by spells and in some cases completely countered by them. The Witch's recent buff, allowing her to one-shot equal level Skeletons, has gone some way in improving the overall crowd control abilities of troops with an AoE. That said, they need to provide more value for their elixir cost. The Dark Prince is an excellent concept, yet statistically lacks power.