I quite like the Crucible, particularly Control and Skirmish (3v3 TDM with revives).

However, I completely agree - the PvE side of things feels incredibly light and shallow. The story is like the shell of a short story and the bosses are all just larger versions of standard enemies but with way more health. Seriously, take the Vex Gate Lord and the Vex Nexus strike bosses; both are essentially larger (ooh scary), bullet-sponge versions of the Minotaur and Hydra respectively. In fact, the Gate Lord doesn't even teleport at you like the minotaur, it just has a big gun and a stomp attack (like every other boss). The Nexus boss has the rotating shield, but it doesn't use it intelligently - it's just there as an annoyance. For every single boss fight, it's actually a relief when the extra standard enemies (adds) spawn in; they are way more fun to fight.

I'm not so much disappointed as mystified. Where is everything? Where is the space, the exploration? Where is the wonder? The story?

This is the only frequent complaint that I don't much understand. If you play all story missions and strikes, I feel like there is hours and hours of content. Comparable to a newly released Halo game. Yes, it is certainly tiring repeating the same spaces over again, but this is very common and has bee used in plenty of well-liked games with success (even Halo). And there is a lot of physical space when you take all the "dungeon"-type areas into account.

I think people have a tenancy to "feel" like there isn't much geometry simply because they always see the start of a given planet over and over again. I think the real issue here is one of presentation and things that Bungie said pre-launch. Having only one area per planet really gives a feeling of being cooped up or contained in that area, even though the areas may sprall on and on.