The third volume of Heroes came to an end this week.

And while we've been openly critical of most story lines this season, the concluding episode did leave our staff with a few reasons to hope for an improved fourth volume.

Therefore, as viewers wait until February 2 for new installments of Heroes, here's our take on what was promising and what was problematic about the conclusion to volume three...

PROMISING: Nathan's evil turn. Arthur was never a believable villain. He was too sarcastic, we had no background for his motives and his powers were never fully explained (or logical; he just showed up in the past and took the catalyst from Hiro? That was easy!).

But we bore witness to Nathan's conversion, as he saw the possibilities of powers first-hand during he and Peter's trip to Haiti. Sure, he turned to the full dark side rather quickly, but we can accept such an immediate conversion in exchange for a morally complex villain going up against his brother and former friends. Juicy stuff, indeed.

Fans are seeing a new side to Nathan Petrelli.

PROBLEMATIC: The lack of build-up for the third volume finale. It's Television 101: events throughout the season of a show are slowly built up, with momentum and suspense leading to an emotional and/or action-packed climax in the finale. Perhaps no show in history did this better than the first season of Heroes, as story lines converged for a world-altering battle in Kirby Plaza, remember?

For weeks, viewers were enthralled by the mantra of "Save the Cheerleader, Save the World," as well as by the deadline of an exploding NYC.

But what did we have in "Dual," the finale to Heroes' volume three? The main focus was on Sylar trapping HRG, Meredith, Angela and Claire inside Primatech. This came totally out of nowhere; heck, Meredith had literally not been seen for four episodes and now she was being thrust into the finale of the volume.

Remember a few weeks ago, when the show seemed to set the sides of Team Primatech vs. Team Pineheart? We were excited for a showdown between good and evil, but one never came about. The entire chapter was titled "Villains," yet new characters such as Knox and Flint were scarcely used. It all reeked of lazy, constantly-changing writing.

PROBLEMATIC: Anything involving Knox. First off, this character was played by Jamie Hector, well-known for his portrayal of Marlo on HBO's The Wire. Yet Knox/Hector was barely utilized. Secondly, wasn't Knox working for Arthur this entire time? Why would he have done so if he was against the use of the formula?

Lastly, the second-to-last episode of volume three ended - supposedly ominously - with a super-powerful Marine... who then had his neck snapped by Knox in about half a second in the finale. Weren't we supposed to be afraid of how the formula would affect those it was injected into?

PROMISING: The initial set up for "Fugivites." We have an established villain, Nathan. We have a simple story line: capture everyone with abilities. And we hopefully have a straightforward set up that won't require jumping from the past, to the present, to the future. Keep it contained. Keep it exciting.

PROBLEMATIC: Mohinder and Tracy are still alive. We don't wish unemployment on anyone, especially in this economy, but come on. What purposes do Mohinder and/or Tracy serve at this point? What connection do they have to anyone else on the show? Many of Heroes' problems are due to its ever-growing number of characters.

No offense, Sendhil Ramamurthy and Ali Larter, but we'll be happy if the car you're now sharing drives off a cliff.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.