@Aedes,
I only know Valjean through the musical, and while it's only a shell of the novel, I do get the skeleton of the character.
What's plain about Dantes is that he consumes his life with vengeance, hidden under this superficial shell of his assumed identities. In the end he finds his vengenace is destructive to innocent bystanders and hurting the people he cares about (most importantly Mercedes), and this tempers his vengeance against Danglars.
But what is clear is that someone like Dostoyevsky would have handled this far differently than Dumas. The internal conflict, i.e. the incipient self-destructiveness is only too superficially addressed. Dumas focuses very heavily on events, but his only "complex" character is Dantes, and one never really sees the deep conflict inside him. It would have been better if this were explored in more depth, in fact it would have perhaps been better if this were central. But as do the other characters, we sort of look at this guy, this Count of Monte Cristo, from the outside and seldom see the inside.
Of course Dumas was telling an improbable adventure story, but I agree with you that he was interested in themes of salvation, vengeance, hope, hopelessness, patience, and temperance. But a better telling of that character would have given more insight into the internal conflict, the internal dialogue, the internal torture.
If you've read "Notes from Underground" by Dostoyevsky (I speak mainly of the second part), which is a very short book, you'll see how easily the irrational conflict within us can be effectively told.
Not that this is damning to the Count of Monte Cristo, because it's an extraordinarily envisaged world and a gripping story.