I guess a (somewhat perverse) argument could be made that the defining characteristic of gambling is that you might (just maybe) get back more money than you put in. In Game of War you are absolutely 100% guaranteed to get back exactly 0% of your money every single time, and thus there is no gambling involved.
And to me it's a slippery slope because what separates stuff like Game of War and Farmville from your average AAA game with purchases for packs of things like skins.
Usually people don't group those because you're paying money for the former up front, but the mechanics are the same.
There's no slippery slope. The difference is easy to distinguish.
Is real money a substitute for skill at whatever decisions the game asks you to make? If so, you're being scammed.
Content expansions in AAA games are obviously not substitutes for skill.
Nor are cosmetic customization options like skins or accessories.
Cards in virtual card games like Hearthstone get a bit more interesting to analyze. There are better and worse decks, and it takes the right cards to build better decks. Spending money is a much faster way to get the right cards than doing daily quests. But there are two factors that keep Hearthstone out of scam territory. First, someone can get any card they want without spending money, and if they're really good in drafts, they can even do it relatively quickly. So, the more skill you have, the less spending money helps you. Second, there's a maximum that spending money can help you. Once you have the decks you want, whether you win or not comes down to skill (and some luck) in the exact same way as everyone else. You get no advantages over someone who built the deck they want without spending money.
So yeah, there's a simple framework to apply to make these decisions. Where's the slippery slope?
I wasn't referring to Content expansions, I was referring to games like Halo or Fifa where you can buy (or earn) a "pack" of "cards" that unlock (non-cosmetic) items that are in the base game that you use in actual gameplay.
In these mobile IAP-fests you can unlock anything with "enough play" and beat most challenges with "enough skill" but the idea is "enough play" is supposed to be so much that if you committed to it, you'd have better luck working a job to just pay for the items you unlock. And there's no difference between items earned and bought, just a difference in expected quantity one has access to. So those games pass both tests you mention.
You end up needing to add more and more constraints to have a framework that works on multiple genres and eventually you'll find you're making exclusions that aren't really fair.
what separates stuff like Game of War and Farmville from your average AAA game with purchases for packs of things like skins
Personally I see two potential criteria of separation.
1) to what extent does paying money increase my chance of 'winning'
2) To what extent does not paying money make the game less fun.
As long as I can have fun with just the base game and have a reasonable chance of 'winning' then I'm not too bothered. But once they start to make the base game more boring or unreasonably hard to 'force' people to upgrade then it starts to become an issue.
