I expected a more interesting, intense political drama...but it's too slow and I am still not hooked into it even after 12th episode.. Before watching this drama, I watched "The disguiser" and I was completely hooked in the disguiser though...

Can't say that i dont agree here. Coincidentally I put it on-hold at exactly the 12th episode. Although I wasn't hooked, I'd like to give the benefit of the doubts coz most people say this show is amazing. 
I was kind of bored like you until about episode 19! After that it just keeps getting better and better though! Now I'm on episode 28 and quite hooked I would say :P
I remember it is indeed slow at the beginning but this builds up the tension.
Nonetheless not because many find it amazing does it mean you will. It all depends on what you're looking for in a drama. Personally I haven't seen anything so close to perfection and satisfaction, but that's just me.
Come to think of it.... I watched The Disguiser because of the characters in NIF. I didn't like it that much because the romance part was stronger yet the pairing was really a fail. lol
I've been watching with a friend and we've both been completely sucked in.  We are intrigued by the political plot.  It's great.
Keep watching. Once you get hooked up, every minute is enjoyable. BTW, despite labeled as 'romance', it doesn't really have romance in it. So if you're looking for the romance, it'll probably feel very slow
So Johnson Khundrakpam, have you finished it?
It took me until episode 20 and a few months. But it was so worth it. 
Yep, same here... ep 20 is where it picked up for me. I finished the whole thing in a few days. I wish the characters from the past were more fleshed out, and while the ending is the best way to go and have no complaints about what happened to the characters, the execution still felt anticlimactic to me. 
I keep hearing about how much everyone loves this, so want to finish it. The synopsis of the story totally sounds like something I'd love, but I keep falling asleep every time I try to watch it. The characters all seem so reserved. I don't have any feeling towards the main character. All the stuff that happened to him and his family that is supposed to make you care for him and his revenge plan is just talked about but not shown. So much of it is just dialogue and complicated plotting against characters that are supposed to be bad, but you don't really see enough of the characters that he is getting revenge on to really care. It's like watching someone talk about the moves in chess match. But reading this discussion, I guess I need to somehow get to episode 20? I don't know if I can do it. I think I'm only on episode 10 or something.
Yeah, fell asleep a few times as well.  It was all talk. And I didn't even know who he was referring to as well. But it's all good now. 
UPDATE: I finished it and agree. To me it was all worth it! I loved it in the end.
It took my around 18 episodes to get into it. 
I'm here for Hu Ge this was the first time I saw this actor, this is my second viewing, his character is playing very important role since he is moving the pieces. He wants justice, sometimes using cruel methods, people getting the fruit of what they planted. The characters are very well portrayed. I'm new in Chinese dramas and movies, I love it. they have a different pace. Also enjoyed "Princess Agents".