1) Which character had the strongest emotional arc?
2) Which character drove the most story?
3) Which character had the most key focus in their scenes (and in scenes not involving them)?
4) Which character interacted with the most characters?
First of all, these are the characters that I consider lead: Elena, Damon, Stefan, and the secondary leads are Caroline and Bonnie -- they've driven multiple episodes, and have been the lead B-story in more than a few episodes). They are all regular cast members and main characters (ie, even though Katherine is played by lead actress Nina Dobrev, I don't consider Katherine one of the main characters). Alaric, Jeremy, Vicki, Jenna, Tyler, Klaus and Matt fall under the supporting roles for me. While we've seen them lead some stories, it's generally the B-story, and more often than not, they are supporting.
Central Character Per Episode (The Vampire Diaries) -- 1| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
SEASON FOUR, Episodes 10-15
4.10 - After School Special | Elena Gilbert -- Other than the B-story, where Rebekah doesn't factor, she actually takes (or ties) all four categories. However, as she isn't a lead, that brings us to default mode and Elena grabs this default. She interacts with the most characters -- her phone call with Damon gives her that one, and she also drives both A and B plots. The latter more strongly as the Jeremy-training is all about getting her the cure. As for the A-plot, it revolves around the cure and Elena is a key driving force that works in her favor too. Elena is also the primary focus of almost all of the characters at various points. Finally, she began the episode not particularly happy with the state of things, and ended the episode with a realization of love and a smile.
4.11 - Catch Me If You Can | Damon Salvatore -- Damon had the closest thing to an emotional arc -- at episode's beginning, he had some degree of control and was awaiting Elena (post-love declaration), but by the end, he was locked up, under Kol's control and denied Elena's presence. He also drove the most story by putting himself in Kol's way to protect Jeremy, and then following Kol's compulsion, led to Elena and Jeremy's actions and plan-making. Damon also interacted with the most characters, and focus was on him by almost every character at some point.
4.12 - A View To A Kill | Elena Gilbert -- While Damon had the most focus -- by default as the only lead who had any central focus on them, and once more had the closest thing to an emotional arc (locked up at the top, freed from compulsion and the cell by the end), Elena captured the other two categories. Not only did she interact with the most characters, more importantly, she drove story. And she drove story in a HUGE way. Just about every single thing that happened in this episode was driven in some way by Elena and because of that she definitely gets this one.
4.13 - Into the Wild | Bonnie Bennett -- In the A-story of this episode, Shane was clearly the central character, but since he's not a lead, we go into default mode. Technically, none of the leads are actually central any more than the other, so turning to the B-story, Caroline has potential. However, that story is so tangential to the main plot that it's not central to the episode at all, so we go back to the A-story. Elena has the most character-driven interaction with more characters, but the focus overall is more on Bonnie as the needed witch whose life is threatened. She also has the closest thing to an arc with her full realization about Shady Shane. Finally, as the needed witch, Bonnie drives the story as much as Elena's desire for the cure and Jeremy's Hunter status. So, by the mightiest of defaults, Bonnie finally gets one this season.
4.14 - Down the Rabbit Hole | Bonnie Bennett -- Like last week, none of our leads had a true central focus, but unlike last week, neither did a non-lead character. In this episode, while Stefan interacted with the most characters, and Elena had the most key focus, Bonnie once again drove the most story (even if only nature of her witchy ways), but more importantly, she had the strongest arc. She began the episode with a fair degree of control, before taking over from Shane completely, but by the end, she was dying, incapacitated and helpless while Jeremy was killed. So Bonnie gets another one... and one more than Stefan this season so far.
4.15 - Stand By Me | Elena Gilbert -- It's fairly obvious that Elena is the only possible choice for the central character in this one. Bonnie interacted with more characters and drove more story, but the emotional arc and key focus was about Elena and so incredibly so that this is one of the most obvious central character choices ever.
CURRENT TALLY --
Elena - (S1) 7 | (S2) 7 | (S3) 8 | (S4) 8 = 30
Damon - (S1) 6 | (S2) 9 | (S3) 8 | (S4) 4 = 27
Stefan - (S1) 6 | (S2) 1 | (S3) 3 | (S4) 1 = 11
Bonnie - (S1) 1 | (S2) 3 | (S3) 2 | (S4) 2 = 08
Caroline - (S1) 2 | (S2) 2 | (S3) 1 | (S4) 0 = 05
Damon led the way from the second season on, but Elena has now passed him and the two of them more than double the next closest character (Stefan). With the events of "Stand By Me," I really don't see how Elena doesn't continue to get the bulk of episodes. However with this show you never know and I do see potential for Damon or Bonnie to grab a good number. Still, Damon is the only one who has a shot of catching up, let alone surpassing Elena at this point.