I don't disagree, but...
I love the game. I have about 70 hours into it going by the 3DS Activity Log. I finished it initially on Normal/Classic and was disappointed when, by about Chapter 10, my characters became God-like and I dominated the rest of the game with little in-battle strategy. How to use my money, XP and Seals to put together an amazing team? That's really fun strategy. The polish on the game is off the charts. It's my favorite Fire Emblem game outside of Fire Emblem 7. That said, the reason why it's only #2 is precisely because the preparation stuff can break the game in-battle.
I started a Hard/Classic run and it was really really hard initially. I lost characters and I had to let them stay dead. I was that weak and the enemies were that tough / numerous. Unfortunately that's broken at this point. I think I'm on Chapter 14 and I already have 5 or 6 party members who are unstoppable and rarely take damage. The pairing system (getting in two shots at once) + the skill system + the ability to grind is just too much. I personally withheld grinding, but kept pairing. I couldn't make it past Chapters 4 and 5. So I grinded 1 DLC level twice. That was enough to round the corner with a Pegasus Knight so she didn't die instantly. After surviving those chapters it only took a few loot drops and some strategic XP usage and my team was unstoppable.
I'm not sure if this game can ever be fixed in that respect. At least not without more fine gradations of difficulty. I'd love a difficulty between Normal and Hard and the ability to completely toggle off non-DLC and random battles.
I have somewhere near 90 hours or so logged in my 3DS Activity Log for Fire Emblem: Awakening but it still hasn't topped my play time for Kid Icarus: Uprising.
I've played a bit of the first Fire Emblem game that was released in the U.S, so I thought playing Hard/Classic would be suitable for me. At first, it seemed like a good match for me (in terms of difficulty/challenge) but as you said it yourself, this game gets pretty easy once you understand how to get the most out of your units. Going by the looks of things, I don't know really if the game gets dramatically harder on Lunatic or if people are just overwhelmed by the new sense of difficulty of the game.
However, once your skill stats get high, the only weapon you'll really need/use are the Killer weapons. At least, that's what I found.