It's hard to dispute most of the negative press that has accompanied this latest iteration of the Duels franchise. It seems, at least in its release form, that the desire to allow players versatility in deck design is mitigated by the lack of diversity in the card pool.
There are some frustrating inconsistences in the game (that perhaps harken back to the 'unlock cards with each win' systems of previous versions of the game), though these are mainly limited to the card pool and deck design process. Many of the cards of which you would want play-sets (especially early drops or higher rarities) have only two or three copies making for some maddenly inconsistent mana-curves. Perhaps this is so players can't create oppressively consistent decks, but it does detract from the idea that players have 'total creative control' in deck making. Duel-lands are clearly in the game - the AI utilises them in many of their decks - and yet players only have access to Guildgates for their own use. Each color can unlock singletons of two mythics, two-sets of nine rares, threes of uncommons and fours of commons; it appears Wizards have been keen to keep the power level down, overall, perhaps in an effort to preserve the newcomer friendly background that has been at the core of the Duels franchise in the past (though this version certainly appeals and rewards those with knowledge of the game). And, true, a few fan-favourite game modes are missing from the 2015 release of Duels; Wizards themselves have been quick to admit their error in this in the wake of strong player reaction.
Despite all this, the gameplay in Duels 2015 is generally terrific. Building your own deck and piloting it through the traditional challenge-based campaign is great fun, and as you unlock cards after victories the process of refining and evolving your deck/s is rewarding. Gameplay is smooth and generally fast (if you turn off some of the combat animations and hold priorities), and clear enough in its visual cues that experienced players can gauge the passing of priority and phases to weigh in on 'the stack'. The AI is definitely improved, though experienced players will quickly find it no match once the AI-weighted campaign is concluded. As each game progresses and the board-state complicates, you will find the AI turns dragging out as it 'considers' its options, though it will still make those head-scratching plays that traditionally plague CCG AIs. And, of course, the AI never concedes.
The optional in-game purchases can add some upgrades to the free-to-play card pool, but the vast majority of game content can be unlocked by completing the campaign. The menu interfaces can be annoying at times, and the need to 'equip' a deck (rather than selecting it at the pre-game screen) is cumbersome, but most players will be spending the vase majority of their time in the card-collection and deck-building screens when not in-game, and these were improved in a recent update. It's all serviceable, at the very least, and not enough to detract from the overall play experience.
Duels 2015 is to be recommended to Magic and video game enthusiasts alike. While MTG players may have been wanting a graphically improved version of Wizards' beleaguered 'MTGO', it's still a lot of fun to play and to play around in, despite lacking the total freedom of its online big brother (though, with some semblance of stability). The card collection and menu interface can be frustrating, but this doesn't necessarily detract from the overall gameplay, and at the price point there's a lot of value and fun to be had. It's safe to say that Wizards have learned from this version of Duels, and the game is likely to receive at least one content update featuring new cards, based on their past processes. So, until Duels 2016 (the franchise is becoming as inevitable as Madden), Duels 2015 is still the best looking Magic game going and offers plenty of entertainment.