I wholeheartedly agree with your issues and the solutions you are proposing Juzzie.
The other concerns about the amount of C/UC’s, Roulette and Duel matchmaking seem very valid as well.
Things that may be done to alleviate those could be:
(a) Make Basic/Adv. Boosters contain C/UC cards from every Expansion.
This would give a wider variety of cards to new players and allows advanced players a cheaper option to hunt for those.
The main concern about this is the lack of creature cards at those rarities in the Expansion sets, making draws unbalanced between creatures and equips/uses.
(b) As proposed, lock row 1/2 from daily Roulette after x logins, promoting daily login even more.
In addition milestone rewards like some coins every 10 days could maybe implemented.
I’d also like to add, I really liked bmuell’s idea about how to smooth out the progression on evo crystals and share his concerns about the power curve while leveling, just comparing cost/benefit factor between Snail 2→3 and 3→4 makes my brain hurt.