On Stealing storylines as a crutch
The storylines have been told time and time again, long before X-Men, Watchmen and whatever other men that we are all familiar with and somehow presume to be the inspiration for anything involving super powers.
On the Price Tag
That's why Heroes can't afford to stagnate like they decided to do in pre-production in season 2. They can't afford to just keep what they have. In order to be more profitable they would have to reach more people, which means changing things and taking risks and learning to keep the beloved things while still adapting. Instead, they went fans-only in S2 and lost a lot on nearly every front.
Regardless, The computer effects they're using are almost abusive, imho (The train scene with claire was just her in a field, no ocean, no train, no tracks, no flying Peter, just CGI)... and if those are their 'effects' then yeah, obviously money is being wasted on things that do not tell the story.
On New characters
I think this is NOT the problem. New characters introduced well with interesting storylines and purposes and depth to them are well accepted, no matter the series, no matter the timing. The problem with adding new characters only comes when you refused to get rid of the old ones, or force the old ones to stay in the middle of the spotlight, which causes bad storytelling, plot holes, as well as makes new characters clog things, because your cast still has the arrangement from S1, with little room for newbies.
Thoughts...
If Loeb and homeboy are behind the stagnation, if they think that the Heroes Universe should revolve around the Petrellis, then this is the only chance that Heroes has to survive and had to be done. If they aren't the culprits of Heroes' stagnation, this was a uber-stupid move, and really is kind of the death knell for the series, because of the timing, position and profile of the fire peoples, regardless of your opinion of their talent.
On Holy-**** endings
Yeah, they're getting back to them. But they aren't as good as the S1 ones, because they aren't built up to. They are random, like the LOST Holy-**** endings, as opposed to "why didn't I see that coming?" like a lot of the S1 stuff. Also, the S1 endings often helped flesh out characters instead of just advance the plot.