I found the game too easy after completion, but I just finished Triangle Strategy on hard mode and that's a more challenging experience overall, so that may be part of the reason.
Anyway, I think I liked Kingdom Battle a bit more? I am definitely not a fan of the exploration phases... it was my least liked part in Kingdom Battle and here they are boosted significantly and take way more playing time. The free movement during the combat phases is fine I guess but mechanically doesn't deviate too much from the original. Also, I wasn't a fan of the battles taking part in areas not integrated with the world. I understand the reasons behind that, but the first entry was at the end more "elegant" solving that issue.
Also, as a second note, there is something "off" about the game in relation to the menus and UI that is common between the -bornproducts working with Nintendo IPs that I don't relly can't point exactly what is but at the same time is reallt evident to the feeling of the game for me. It happends with Mario & Rabidds and it happens also with Next Level Games products. They just don't have that "Nintendo-feel" to them.