Some micro transactions are tolerable, some of the time, but every single one of these commercializes the product. IMO if they exist, the game should be free-to-play. Where I really get annoyed are games like Lego2K (racing game) where you pay $60 to play, and then it's also full of microtransactions (for cars, courses, cosmetics, you name it).
I think it's a different matter when it's a content-filled DLC add-on to the game. Yes, the line for that is a bit arbitrary, but the classic example would be Starcraft: Brood War (well, technically that was an expansion pack, but same idea). Adding a single additional course to a racing game blurs the line, I generally think content should be bundled so the gamer isn't constantly making financial decisions while playing.
I don't see governments doing this, but I think we'll see something like this soon in the EU when we can install competing app stores.
Maybe we need a pornography-like definition ("I know it when I see it") but I think there is certainly a continuum from high-quality DLC / expansions to existing games (which can be basically a new game) down to crystals which allow you to instantly buy something which you'd have got anyway if you had waited.
So, consider a basic, Mario-kart like racing game - which of these are OK, and which are micro-transactions?
- buying additional courses,
- buying additional characters (drivers), vehicles, or components of vehicle (e.g. wheels, engines, bodies),
- buying purely cosmetic changes (e.g. driver outfits, vehicle colours),
- buying permanent upgrades to your vehicle(s) (i.e. more speed, better acceleration, better handling)
- buying one-off power-ups that last for a single race, or are time-limited (+50% acceleration for 1 hour)
- buying 'cheats' - obvious play-to-win items (e.g. needing to complete 1 fewer lap than your opponent),
- buying regular game-progression; e.g. maybe 100 races/wins/hours of play are normally required to unlock all courses, but this can also be instantly purchased.
- any of the above options, but not bought directly, but rather via purchasing 'crystals' which can be exchanged for the above.
- any of the above options, but in a 'gatcha' style (i.e. loot boxes; you cannot choose which upgrade you want),
I think I'd be totally OK with the top three, maybe OK with buying permanent upgrades, and unlocking game progression (in this case), but the others are too far for me.