In my case, I loved the gameplay to the Advance Wars games, but I couldn't stand the tone. The first game was the worst, where characters treated their soldiers like Pokemon, throwing armies to battle each other to the death on a whim, and I really dislike the idea of having children leading armies that is so prevalent in anime in general anyway. I loved the first three Advance Wars games in spite of this, and the second and third games were better about the tone, and significantly darker in general, but these are games where hundreds, if not thousands of soldiers die. It's not a problem to have silly, funny soldiers if you don't have a story, like Famicom and Super Famicom Wars, which are basically the War Room, but if you make characters and a plot, it just doesn't work because you have stepped away from one layer of abstraction already.
The games require slow, thoughtful gameplay as you progress to the more advanced levels, so an upbeat, fast paced, zany plot wouldn't really seem all that appropriate to me anyway.
That said, as much as I loved the massive volume of content in Dual Strike, and even enjoyed the action game, the CO power Tag-teaming reached an utterly ridiculous level and utterly wiped away most of the strategy beyond feeding CO powers. The intricate system of checks and balances between units couldn't stand up to things like Colin's (admittedly fun) level 2 power. The powers gained through experience made it even worse.
If days of ruin had had the War Room and some of the other bonus content, it would have been perfect, as, sadly, there just wasn't as much game to love, and the other Advance Wars games basically had Famicom Wars (and I believe also Super Famicom Wars) included almost in their entirety, aside from unit tweaks and the CO's and leveling from the Super Famicom game. I loved the story, character design, and mood, but I especially loved the renewed focus on units and the new strategic choices offered by the toned down, but still very useful, COs. The addition of the anti-tank and the motorized infantry, along with new features and massive tweaks to old units, made the gameplay fresh and provided tons of unique, interesting options. I adore Days of Ruin, and I really would love to see something else like it again.