Hmm... Okay, I agree. In general, borrowing elements is a problem. I was really surprised when I heard music in Heroes 7 during a battle that was also used in CoH (and later successfully transferred to Heroes 6, where it plays in almost all battles for the Knights). The music is good, but it's too much.
Ples, I didn't say the graphics were bad. Rather, I was referring to the point you wrote in white font. It's just hard to believe that so much effort was put into it, considering the price of the game. With Divinity: Original Sin, which also uses partially borrowed music and models, it's the same.
Regarding the partial 3D a-la Heroes 3... Well, yes, it could have worked. But then they could have made it fully 3D. It's 2015, so it shouldn't be a problem, I don't believe it.