I don't think Buffy was any less a hero in this season.

[Benz]

After watching this season I really don't think Buffy was that depressed as she seem as she still was saving good guys and fighting bad guys.

Sure she had her moments when was not herself this season but I do think she was or less back to normal sooner then it seem onscreen.

 

[Ethan Reigns]

There wasn't a real Big Bad in Season 6, so there were no heroics to be had. You could say Dark Willow was the Big Bad, but Xander handled that on his own more successfully than Buffy, Anya and Giles put together. You could say The Trio was the Big Bad but Dark Willow dispatched Warren and put the fear into Andrew and Johnathan. The Big Bad appeared to be adult life, itself. The combination of low cash reserves, waking up from being dead, dropping out of school, being Dawn's guardian, getting shot one bullet before Tara and of course what to do with Spike (her answer was to do Spike but hate herself for it) all conspired to initiate and continue the state of depression.

I don't see her doing much saving - she assisted Riley with Spike's demon eggs and failed in her attempt to kill Anya but probably cost Doris Keller, the social worker her job by abusing invisibility.

 

[thetopher]

I'm trying to think about people Buffy actually saved in S6:

Beat the Hellions- or at least some of them- and caused them to retreat. But...they were really lame so, call it an assist.
Failed to stop a bank robbery in 'Flooded'. Defeats demon but it costs her a lamp, full copper re-pipe, and Giles getting knocked out again.
Life Serial? Nope, she got fired and then got drunk. She did save some construction guys from demons I think. But then again the demons where there to kill her.
All The Way: she saved Dawn and Giles, so that's something. Still, Dawn put herself in danger the little twerp.
Once More With Feeling: Uh, Scoobie caused it, some people die, Scoobies lose to Sweet as a lot of painful truths come to light. Ooh, Buffy did save some shirtless guy from being sacrificed. Whilst singing.
Tabula Rasa: Buffy saves Spike from *sigh* the loan shark. The rest is everyone saving themselves from Willow-hijinx.
Smashed: Buffy stops a mugging, but not the museum heist.
Wrecked: Saves Dawn from Junkie-Willow and demon.
Gone: Attempts to drive social worker mad.
Doublemeat Palace: Actually saves people from death who are not Scoobies!
Dead Things: Framed for murder, boinks Spike, not much else apart from making Dawn cry.
Older And Far Away: Actually harms people by taking a magical demon-sword into her home. It's like a Summers tag team event. One traps them all, the other brings the bad guy.
As You Were: Quaintly old-fashioned since Buffy actually kills a demon, helps avert demon egg apocalypse, and foils evil-Spike.
Hell's Belles: Not really. The demon got what he wanted. At least he gets dead though.
Normal Again: Tries to kill her friends in a hallucinogenic frenzy! Kills evil demon that she put in the basement to kill her friends.
Entropy: I can't remember. I think she kills a couple of vamps whilst out on patrol.
Seeing Red: *blotted out memory of episode*
Villains/Two To Go/Graves: Protects two nerds from Dark Willow after Dark Willow saves her life from bullet wound. Gets smacked around by DW, Giles and Xander save the day.

That's about it. Not a stellar record for that season really.
But then again I was never really bothered by what Buffy didn't do this season, only by what she did.

 

[GoSpuffy]

I think Buffy was just as heroic in this season, maybe more so. She was depressed but some how she kept going and pushed herself to stay in the game despite that. Anyone can be the slayer extraordinaire during good times, how we really know our measure is when we have to pull ourselves up from the depth of despair and push through it and remain true to ourselves. Season 6 made me really feel for Buffy, to understand how alone she felt, to realize that she was the hero who put others first even when she was suffering.

 

[thetopher]

to realize that she was the hero who put others first even when she was suffering.

That's the thing though, Buffy didn't really put others first *points at Dawn*, she was very self-involved.
I get why she was self-involved because of her pain, and I don't blame her for that part at all...but it kinda strayed into self-indulgent territory later on; totally ignoring her friends, using Spike to feel good even though she didn't love or even like him, sabotaging the social worker who had legitimate concerns about Buffy as care-giver.

I just can't see Buffy as more heroic this season just because of her problems (she always had problems of her own- Angelus, Dawnie, day-to-day slaying.
Perhaps you could say she was at her most relate-able/normal, or at least you could make the argument.

 

[RomanticSoul]

Just the fact that Tara died as a direct result of Buffy sleepwalking through the Season (when not too busy with demon boinkage) is proof enough of that. How hard is it for a Slayer to apprehend a couple of human geeks? And hey Spike freaking knew where Warren lives (because of Sex bot) if I remember correctly. So it's partly Spike's fault too but at least he has the evil excuse.

 

[Guy]

I see it as Buffy being an incredible hero in seasons 1-5, with season 6 finally making Buffy act like a human. A human who falters, and loses faith in herself, and makes mistakes, and neglects her duties. It obviously wasn't her best behaviour, but on the other hand, it wasn't BAD behaviour (for the most part) either, and it is the kind of things that most people do all the time for far less justifiable reasons. Buffy's behaviour in season 6, given the challenges she faced in it (compared to the earlier seasons), is more heroic than ever. People who say that Buffy was being "pathetic" or "a bitch" or whatever are just holding her to an impossible standard that no human can live up to.