I couldn't stand Ni no Kuni either. I made it half way through that game before I dropped it because I was just so immensely bored with it. I think I lasted longer with Tales of Graces f, which should say a lot because I didn't care too much for that game either, lol! Not that I want to generalize, but I feel like Ni no Kuni is for people who don't normally enjoy or play RPGs very often. I also feel like the game emits an almost fake level of nostalgia. It's like, the game was marketed as a "classic" RPG and a "return to form" of sorts, but I don't remember any SNES/PSone-era RPGs playing like that game. It's like, people saw an old school overworld and they immediately thought it was a classic. =/
Like most Level 5 games, their visuals and attention to detail/presentation is what captures most people. Ni no Kuni excels in those areas, but it severely lacks in other, more important areas. For a monster raising/capturing game, I don't think I've played anything worse in the genre than Ni no Kuni. The fact that the game relies on what is essentially a random drop in order to build a party is horrible. I can't imagine playing an SMT game where after battle I had to rely on a drop rate in order to obtain a demon. It's crazy. Let's not even talk about the character AI either. =0
I can't help to raise an eyebrow if someone says Ni no Kuni is their "favorite RPG" of the generation, etc. Makes me not only question how many RPGs they've played, but also what their values are.