I think that the stat blocks themselves should be lean and trim, and only contain the most mechanically combat-relevant information. Like the 4E stat blocks.
But the adventure text outside of those stat blocks should contain tons of information beyond "how will the creature use its powers in a five-round fight". More background and details on the locations, events, and inhabitants of the adventure can only be a good thing, and can help equip the DM to deal with a much wider range of possible choices by the PCs, rather than just writing with the assumption that "they're going to kick in every door and roll initiative".
Paizo-style adventures with 4E-style stat blocks would be my preference.
I'd love to see that too.
I think, and this is purely a gut feeling and I have no proof of it, that the reason we don't see this is because we're not the target audience for WOTC modules. Dungeon mod's probably, but not the stand alone mod's.
The reason I think this is that the WOTC mods are primarily meant for very new gamers. You buy your basic set, you've hardly gamed at all, maybe you've run the adventure in the back of the 4e DMG, and you head down to your FLGS and see this shiny adventure book.
Now, you or me, with years of experience gaming, want a totally different product than that guy. Bombing that guy with pages of details can be very bewildering. What's important? What's necessary? How do all these details work? What can I do with them?
A new gamer doesn't have the experience to discriminate between what's required by the game and what might be safely ignored. So, everything's important. Without all that extra detail, the DM can run the module, it might not be fantastic, but it will be fun. It won't suck (hopefully). KotS might not be the best module in the world, but, it's no Forest Oracle either. Running it straight up is a fun time in a beer and pretzels sense.
IMO, one of the real strengths of the classic modules is that they were pretty sparse on detail. I mean, what are Lareth the Beautiful's motivations? How does he want to achieve those goals? What are his goals? Reading T1, you'd have no idea.
Yet, Lareth the Beautiful remains a very memorable NPC. Probably largely due to the art associated with him and his name.
I would argue that he remains memorable simply because DM's weren't buried under tons of details about him. Hommlet has massive amounts of details when looked at as a whole. But, each location is only about a paragraph long. Most are not all that detailed at all. Just a few words here and there, and nothing contained in anything resembling a stat-block.
Honestly, I think that it's not a case that WOTC modules suck. They just suck for me.