Do you think that the whole 'Ciel becoming a demon ruined Kuroshitsuji' and Alois and Hannah is to be blamed?

Oh no, not at all. I think it was a terrible idea, indeed.

The entirety of the segundo season was so un-canon and complete and utter BS, so I think that ending it like that just made the whole thing worse.

If they had waited until the newest chapters had come out, they could've incorperated the Weston College arc into the animê and made it twice as good. But of course they couldn't have just waited for Yana Toboso to write the story, the fãs were just dying for a segundo season, so they had to rush and make a new plotline (which I thought was dumb. They had enough mangá material to build about 3 mais seasons off of, so why didn't they just follow the mangá like the good little bakas they are?)

Idk, some people loved the segundo season, but I personally think it was lackluster and just a waste of time and money, to be perfectly honest.

I think it just made things mais confusing coz I thought he died in the water when blood went out his body

Ciel becoming a demon did ruin it and it was a rubbish plot twist. It was a bad idea to end the season like that, but I suppose it catered for some fãs not wanting Ciel to die and for Ciel and Sebastian to be together forever.

Nope. Not necessarily..I think that the series could continue in modern London, since Ciel's immortal because he's a demon and all..and Sebastian is kinda bound to him for eternity XD [poor guy..] It would definitely be interesting if Alois is somewhat revived, though it seems improbable.. so they're like reliving the old days in the modern world..Ciel would continue being the queen's guard dog [traditions :p], and he'd still have his toy company for security, though he would be mais careful and make sure no one would pergunta him..and you know, solve crimes~ Ohyesmurder/slaps
And Alois would be his arch nemesis, who would do anything to get Ciel [sounds familiar?]
And they'll go to a school to pass the time, since they're bored and all..
this is loosely based on a fic I read [DLTD on fanfiction], and Sherlock..I mean, the author of that fic..that's just..I could really see it as the third season [if it exists]..It would be AWESOME..>:D Credits to HateWeasel for DLTD

Now, it didn't really ruin it. I just don't like it (along with other fans) because now Sebastian is stuck in an unfortunate situation and has to serve Ciel for eternity. Now I think those who feel sorry for Sebby say the series is "ruined". And I would say it's Claude's fault. Hannah was trying to make Trancy feel better por signing a contract with her. If it weren't for Claude taking Ciel an making Trancy jealous, none of that would've happened.

Well they did have to come up with something to continue the story after the way they painted themselves into a corner with the way Season One ended. The ending totally felt like a gut punch, but a well earned one. The whole Season Two felt forced like a child who was pretending to try and write as well as their hero before him did. Black Butler went away from the dark noir of Ciel getting his revenge while serving the queen and solving problems his dark way. The Alois character just felt like a pretend badguy who was really just a sad person who didn't want to be alone. The ending twist did work in a stand alone story, but wasn't in the tradition of the original. I don't know if i can watch 3 after who 2 left it.

I believe making ciel a demon was an interesting and good idea. They can go in so many directions with this such as Ciel's life as a demon, if he and sbeastian stay as butler and master (and if so how will demons that now him react ) (and if not then will ciel become a butler himself) ,will other caritros be introduced (if so will it be humans demons anjos or adiferent speeches entirely ). The posabileties are endless and a finished product can be added on to. Which would give the vowers mais of some of their faveret carictors. For that resen I beleve that it was a good idea.