Kamirensa Jewel Heaven" has a system where all cards can reach maximum rarity/strength, and that depletes the pay-to-win feature quite a bit. I would rate that game slightly superior to P&D.These kinds of games are really common in the Japanese iOS store, so I don't think it's that special. I mean, another game called "
...And why the hell are these considered "puzzles"...?
P&D was developed by Gungho, the people who published Ragnarok Online a long time ago. It's had sweeping success on the Japanese scene compared to those other match-3 combat games, and they do quite a bit of collaborations with other franchises and companies which bring variety to the monster collection(HunterXHunter, Evangelion, Batman Arkham Origins, Clash of Clans, to name a few). The game does stay true to it's name by releasing consistent varieties of dragons and other monsters to collect(admittedly, they aren't as powerful as the ones you could get from spending real money for a rare monster), but they're very free to giving out the premium currency of the game during events which do happen every other week or so.
The art style is colorful and cheery, which I kind of prefer compared to other apps that more or less play the same way like Tower of Saviors or Angel Salvation and the like.
Plus, there's a non-IAP version of P&D already: http://www.nintendolife.com/news/2014/01/matters_of_import_drop_matching_and_dragon_evolving_in_puzzle_and_dragons_z