Conceptually dull... well, we'll see. My opinion so far is mixed. Some of the conceptual stuff we've seen is excellent, some is mediocre, a few things are just horrid. So far I'm guardedly optimistic about the fluff side of 4E; I'm sure I'll need to reflavor some things, but it doesn't look like I'm going to have to give the entire book a makeover.
There has been some good fluff, but most of that good fluff has been "supplementary." The info about the formorians, the stuff about the archons, all of that is good, but, so far, it doesn't look like it's going into any of the core rulebooks. Every excerpt and preview and photographed page from the MM we've had so far has been monumentally boring, even going so far as to
actively remove interesting things about the monster (the bodak is the example I keep bringing up, but the phane isn't a bad example, either).
The interesting stuff is in the DDI.
If this perception is accurate, I think it's really boneheaded, and whoever made that decision needs to be bludgeoned with a 13-foot tall beholder statue.
A monster book should always inspire you to use the mosnters in interesting ways, and give you the guidelines that you'll need for running them in those ways. One of those ways, the most important of those ways, is absolutely combat. But combat is not the only way.
The "collection" angle on this guy is pretty weak sauce. The "predatory" angle on the phane is kind of sad. The "it likes to kill" angle on the bodak is hilariously awful.
I think the team will succeed at whatever they really want to succeed at, I'm mostly concerned that somewhere, they decided that giving the DM interesting ideas of plots in which to use the monster was not something they really wanted to worry about for the MM.
I do think it's a big problem, because the monsters in 3e that worked that way were rather universally mocked -- phantontom fungi and ythraks and digesters and whatnot. These were not good monsters, though their mechanics were fine. These were poor monsters because they didn't give the DM any reason to want to put them in an encounter.
Really, I'm kind of ranty about this because this was one of my FIRST fears about 4e, back when they were proud of how fast and easy mosnter customization was, and I've only seen things that would confirm the fear.
*Sigh*. It's a good thing Necromancer is on point.