Machinna - Back in the day when they were the smaller Halo central channel focused primarily on actually Machinima it was great.
It was the home to Arby 'n' the Chief and all sorts of wacky videos from very random people who were brought on due to their talent.
But now days Arby 'n' the Chief is long gone, Halo is long gone, any actually Machinima is gone.
Now all that's left is crummy news videos filmed in a cheap fashion around their office.
The hosts aren't funny and honesty many other channels do the news better.
Any good content is either over or moved on elsewhere and the community is the kinda of "L0L XBONE TOPKEK" thing which I despise.
The Amazing Atheist - Whilst I enjoy is videos about Atheism and the bashing of nutjobs, his channel switched out of Atheism and into just being an anti-Feminist channel, not to mention the consistent videos about Justin Bieber. I mean sure Justin Bieber is a bit of a douche, but CJ has made like a million videos bashing him.
I liked him when he was just doing Atheist stuff, but apparently that doesn't get the views.
Alex S - A dub step artist who grew himself out of literally nothingness into fame by creating Brony dubstep (and quite good ones too), however he abruptly stopped making Brony dub step.
Now don't get me wrong, I didn't unsub just because he left the fandom, but I unsubed due to his abhorrent attitude towards the fandom, claiming that they were holding him back, despite being the very thing which got him where he is.
Not surprising while all his Brony dub step has over a million views, all his recent stuff has like 24k, most of the comments still being from Bronies.
MikeB aka Fony - As someone who loved MMO's I loved his in-depth videos on MMOs which not only were more detailed than most, but also fill up of humour. His "BFF Report" among others was fantastic.
However now days he doesn't do any of that, instead he has switched over to a generic indie game let's play channel full of garbage.
Rooster Teeth - Granted I never really had much to do with them on YouTube, however for many years I had been religiously watching their content on their website, I was even signed up for the actual monetary subscription.
Red vs Blue was great, their Skit show (shorts) was great, their other stuff like Immersion was great.
I loved it all.
However now days their content is obsessed by let's plays, Minecraft and the like.
Red vs Blue has gone dramatically downhill, RWBY is something I don't get how people like and most of their content I feel has had the wit taken out of it.
Rooster Teeth's audience tends to be very young (tweens/young teens), which is fine, I don't think that alone is a bad thing.
Maybe their audience was always that, because it was that age when I loved them and maybe I just grew out of them.
They've never been bigger and I am really happy for their success, but they're no longer for me.