I think you guys need to do a little more research on these rewards systems before you draw these sweeping conclusions about them.
When I hear this, I just think "Why should I take extra research to look up a reward system when other games make it more straightforward?"
Honestly, this is just bad design, if this is not written on the paper how reards work or what the most effective way is to gain rewards.
When I look at Eternal, I can see that rnaked ranked gives me chests, draft gives me cards and gauntlet gives me also... chests? Well, Eternal has some inconstancy int heir rewards but you know that at least you get some... chests which give you... stuff.
Hoenstly, they could be more straightforward with their rewards, the whole "you get chests and the chests might contain other chests" is a little to random for my taste.
Then I look at Duel of Summoners, where they write exactly on the pack what the chance for each individual card is to appear in the pack. I know not every developer might want that inside in their drop rates and stuff but I think Duel of the Summoners is the most honest one out there regarding their rward system.
But besides packs it's also random as hell, you have quests, then you have daily challenges, you have this roulette thing after each win you have arenas, you have story mode... the list just goes on. And the rewards are, while always gems, so randomly decided. It's easy to get your gems for a pack each day but a little more regularity wouldn't hurt the game.
Plants vs Zombies Heroes, which is currently my favourite one, is probably the most straightforward one. You get quests, which give 10 gems each day and you get gems for ranks in ranked matchmaking. Once you reach a new rank (5 wins), you get a gem reward depending on the rank you reached. if you reach a new league, you also get a big bonus (and the league defines your reward at the end of the season).
At the end of the season you get packs (not gems) depending on where you ranked, diamond rank (which is easy to reach) can give you 10 packs.
Additonally victories give you points that contribute to the weekly event card 8each week a new card is released) and if you get 1200, you get this card. Playing the daily challenge gives bonus points and playing with specific heroes gives also bonus points. Sounds actually more chaotic than it actually is, basically, ranked matches give you gems, season ranking gives you packs and normal wins give you event points.
With the third set recently released, the game offers now more variation than before, moving foward to more tactical aproaches. It will never reach the depth of Eternal or maybe even TESL but it has already surpassed Hearthstone (in my opinion) and of course Gwent. This is of course agueable, I bet people would disagree on this.
As for the new set, it's main theme are primeval times with dinosaurs and orimitve plants/zombies. New gameplay elemets include evolution (play on another creature, get an extra effect) and fusion (play this first, play another creature on it, get teh effects from it). Dinosaurs activate hteir effects whenever a card is drawn, included from summons.
Whiel we're at new sets, Duel Links (yugioh) released also a new mini set, mainly machine themed cards but also some magician cards. I got 500 gems free (which translates to 10 packs) for the release of the new set. I honestly cannt remember, what cards I got though, Yugioh has too many cards and when I build my decks, I don't look from which set they are. The game also introduced a new event game mode which is... not very good or fun. Basically, when you win matches, you get dice pieces and you can use thes epieces to roll a die at soem weird boardgame, at soem points you have to stop (regardless of your score) and fight an ai opponent, for wins you get coins which you can use for special event chests. The chests contain cards and keys, I believe some crafting resources as well but I got only keys and cards so far.
I cannot even tell if the rewards are worth the investment in this event.
