I hate when this is said. It's a bit odd to think that people 'don't know what they want'. I know exactly what I want, but the problem is there are countless others who have a similar of ideals. When you try to combine those ideals with mine, you get something completely different than my initial wish.
So, rather than saying people don't know what they want, we can say it's hard to please everyone.
I had a feeling somebody would take issue with it, but it's a generic turn of phrase and I got lazy. I apologize.
What I'm saying is that Zelda hivemind across the net, when their suggestions are taken together, often make demands that Nintendo poorly interprets and implements in future games.
There was a strong push among the fanbase to bring back the "mature" style... which then received a strong re-evaluation as being "bland" and quickly outdated when TP was released. People wanted their sequel to OoT, and then didn't like it when MM and TWW followed it up in weird ways... but when they got the ultimate love letter to OoT in TP, there was a strong backlash against that as well. People clamor the games are getting stale, but then we got the DS Zeldas, which a vocal chunk of fans despise. This "overworld = dungeon = brilliant" movement has also had to re-evaluated itself with SS.
Of course, it's not as though everybody fits in one particular group (and some problems do get resolved satisfactorily, like the HUD problem in SS), but Nintendo's response to the predominant criticism of each of the latest Zeldas has usually only wrought more problems than it solves.