Bolvar Fordragon rocks. He really does. I love him as a character, specifically as a figure of awesomeness that both factions can easily acknowledge. I doubt you'll find an Alliance or Horde player that doesn't know immediately who Bolvar is. His great works have ranged from Vanilla all the way up to the end of Wrath, and silently continue even through Cataclysm.
But is he too good? He doesn't seem to have a single flaw to his character. I cannot recall any moment in lore where he shows the slightest hint of bad judgement or selfish intent. Is he as believable a character as he could be with some more human flaws?
Take a look at some other notable figures in lore. The easiest example would be Varian Wrynn. Yes, he is the leader of the Alliance, and yes, he does do some good work. But most of his good works tend to be side-effects from his own deep-rooted rage and thirst for vengeance. He helped the Horde retake the Undercity after the Wrathgate, but he did so specifically because he wanted vengeance against those who he blamed for the alleged death of Bolvar Fordragon. He is incredibly racist in his hatred for the orcs, and he shows no signs of viewing them as anything with feelings and emotions. In this way, I feel that Varian is a more believable character.
If you look at some other notable figures in lore, the fact that their good intentions were punctuated by moments of - I hesitate to use this word - evil adds more depth to their characters. Maiev Shadowsong, the jailor of Illidan Stormrage, stood guard over the Barrow Dens for ten thousand years. She never wavered in her duty. When Illidan was freed, she saw everything that blocked her from recapturing him as an enemy, even Tyrande Whisperwind.
If you've played Warcraft III: The Frozen Throne, you may recall when Tyrande gets swept downstream and Maiev loses sight of her. Maiev, in order to get Malfurion to continue pursuing Illidan, tells him Tyrande was torn apart by the naga. She lied in order to advance her own lust for revenge over the deaths of her fellow Watchers and to imprison Illidan once again.
This single-minded obsession makes Maiev a much more interesting character in my mind.
I must reiterate that I think Bolvar is awesome. I think he's done some really kick-ass things in the service of Azeroth as a whole, regardless of faction. But I do feel he could use some kind of darkness. Something needs to shock us. The players needs to be amazed that their once-glorious hero could commit some act of cruelty or malice.
I'm hoping that his current state as the Lich King will provide that very avenue somewhere down the line. However, I doubt very much that Blizzard would be so willing to sacrifice their greatest hero to progress a storyline that would be equally epic.
I can imagine some expansion down the line where we, the players, "discover" what happened to Bolvar Fordragon, and then discover that the entity of the Lich King that resided in the helmet, or perhaps some new Old God, has begun corrupting Bolvar and turning him against the very world he swore to protect, even in his own state of undeath.
I know I'd feel some strong emotions if it came down to a moment where we, the players, were forced to kill Bolvar Fordragon. I don't think I'd be alone in that one, either.
I'm starting to ramble a bit, so I'll just get back on point. Bolvar, while awesome, needs to have some more depth. Because as good as he is, even now, it's hard to get a real grasp on just who he is. I would like to know far more about him and his life.