I'm going to post (almost) the entire Graeme McMillan article from io9 because it's so excellent. Here are five ways Heroes could stop being terrible.
Whatever Happened To Fun?
You know why people liked Hiro so much in the first season? It's not because of Masi Oka's cute little face, but instead the fact that he was the one character who actually seemed to find some kind of joy in his powers... a joy that was, of course, completely wiped out when he failed to save his murdered girlfriend because frowning is much more in tune with what Heroes wants to be (Apparently, serious and depressing) than anything, you know, fun. It's a shame - Fun and a sense of joy and wonder is something that this show needs; something to suggest to viewers that it's not always going to be the weight of the world on the characters' shoulders. Not only is variety the spice of life - or so I've been told - but the show lacks the contrast of humor to bring out the weight of the high-stakes drama.
Stop Neutering Your Characters
It's not just that Sylar isn't eating brains anymore - it's that HRG was revealed to be much less a cold-blooded killer than a man who'd do anything to protect his family, Elle was shown to just be looking for Daddy's love, and whichever one of the "villains" proves to be popular will also be shown to actually just be sympathetic and misunderstood. Heroes can't stand to leave their bad guys actually being bad, and the result is bland and annoying. Whatever happened to bad guys that it felt good to hate? I give it three episodes after Adam's revival before he explains that he'd give up that whole "wanting to get into genocide" thing if only someone would give him a hug.
Enough With The Time-Travelling
Ripping off the X-Men "Days of Future Past" plot was fun enough the first time, but will every season involve the characters racing around to try and prevent a future that one or more characters has time-traveled and witnessed? By the time that Hiro bounced ahead to see the latest apocalypse on Monday's premiere, we were bored with this temporal McGuffin. Here's a good hint to the first step in making your show seem fresh and essential again: Stop repeating yourself. Especially when it's entirely unnecessary (The idea of a bunch of escaped supervillains running around and causing trouble isn't enough to base your season around?).
Don't Give Everyone Superpowers
Yes, we've read Earth X and 52 as well, but that doesn't mean that it's a good idea to go into the "everyone can get superpowers" plot so soon in the show's run - It devalues the abilities of your main characters, as well as their uniqueness in the world they're living in. More importantly, if everyone on the show gets powers, you're taking away an ground-level entry point character for any new viewers... unless you're creating a new character called "Really Confused Man Who Wants To Know How Everyone Got All These Powers Anyway."
Cull Your Cast
It's not that we don't like Maya or Mohinder - although, honestly, we don't - but who can begrudge us their sexless sex scene when we'd rather know more about what's going on with FuturePeter, CurrentWeevilPeter, Nathan, NotNiki, Elle, Hiro and Ando, Claire, Matt or even entirely-missing-from-the-first-two-episodes Monica and Micah? There are way too many characters and plotlines going on for an hour-long show to be able to handle coherently already, and we're only two episodes in; anyone attempting to jump in on tomorrow's third episode will be entirely lost. Either work out a way to rotate characters in and out of the show as needed, or just start killing characters off. By which I mean "kill them off and keep them killed" - No more of this "Niki's dead - but here's someone who looks just like her!" or "Nathan's dead - No he's not! And he's brought Lindeman back with him... in his head!" bulls---.