Perhaps you should redefine HARD.
Hard game would mean challenging to me. It would have battles requiring reflexion, strategy. But RSL difficulty has never been that kind of hardness.
It's hard because events can't be achieved without paying. It's not like if you try harder you can get rewarded. If you don't pay, you don't get reward.
It's hard because the RNG is messed up. Like all champions have same chance to get out, but you eventually get always the same ones.
It's hard because high level in dungeon do not even give better rewards most of the time. How many 15th level gave you 4 lesser potion or less ?
It's hard because AI is doing stupid actions like going for an AOE on a boss when it could decrease it's turn meters by 75%.
It's hard because you need 15 books to max out most champions and you can't get book if you don't pay.
It's hard because you can't prepare for event as it's not advertised soon enough. And you only get schedule, not threshold information or how points will be given.
It's hard because they design hundreds of useless champions for few usefull champions only to lower chance to get something usefull.
So it's just not a f2p because F2P games are a category of game in which a free player will eventually get the reward but on a long run when a spender will just get it as soon as it get out. It's a pay2win because you have to pay to win the reward. I can't even see how someone can feel it's a reward when he has to pay (and so much more that it should ever cost).
And paying has never been a game difficulty level. You can't say a game is hard because you have to pay. It's not hard to pay, you do it every week to get food. It's just a paying product and RSL doesn't worth it in my opinion.Too much $$$ for something you could lose tomorrow with no refund and only tears.... think about SB nerf ;)
As for the deepness of the game, i can't see where you found that. Maybe you never played deep games :) If you take a look at the game, you can do most dungeons without bothering. I mean what's the point having 200+ champions when you can beat most of the game with 10 ? Except for arena where you face payers with full team of maxed out legendaries, you don't even need legendaries.
And as a free player i can find games. If we go on gotcha like computer games (because 60$ packs is a AAA computer game price), you can get MTGA, LOL, Dota2. All 3 of them are somewhat f2p gotcha games. You can get heroes/cards as long as you play the games. And if you want to go faster or get some skins you can pay.
Btw If you want a deep game, go for Mtga. A recent analyzis of the game has pointed out no computer would actually be able to do the perfect Mtga game. It's not even like chess or go games. Just there is to much possibility and probabilities to always have the best play.
And if you want a free deep grinding game, you can also go for PoE which is also a free diablo likecomputer game with a skill tree that would make you cry. And some dungeon like instancied area which would give you hard challenge (the kind of challenge you can't pay to achieve them)
I won't speak about phone games as i'm pretty sure there is a forum policy that would allow to sword a post if it's advertising other phone games.
It's really hard to defend RSL strategy unless you are a payer. Because once you start paying such amount for virtually nothing, your brain can't stand the contradiction between i pay too much to get junk. Thus it will make the junk be amazing to avoid being messed up.
Check out for cognitive dissonance. This is how RSL gets you once you start paying :)