I love the King's Bounty games, I really do.
But King's Bounty: Legions just doesn't feel right. All of the elements that made the previous games interesting were removed or tweaked to provide the most bland and generic experience possible to the player.
In this game, there is no specialisation, you can spend your gold on marginal upgrades for units and spells, but cost scaling and level requirements for these upgrades is made in such a way that you can't just decide to dump all your gold into spells and rely on them. Especially since you can't learn spells, you have no mana, you have to buy scrolls, every time you use a spell you need to use a scroll.
When it comes to army building, there isn't much to it unless you are willing to pay, you have access to some basic units from shops, and a few advanced units as quest rewards, but only enough to show you what these units can do and encourage you to purchase more at the real money shop. You just don't get the satisfaction of doing your best with limited resources like you did in the previous games, especially since morale mechanics and most of the units special effects were removed.
Finally, you don't have to select your battles like in the previous games, here you simply progress from one area to another with the ability to grind when you feel you aren't strong enough to take on the next challenge.
The only thing that's left from the previous games is the turn-based gameplay, which just isn't enough to hold the game together without the strategic elements that the previous games had.