The first part, Che in Cuba, is about that portion of his life. It contains too many indistinguishable battles and Che ministering to too many indistinguishable wounded (remember that Che was a physician). It ends as Castro wins the revolution; Che never gets to Havana. The second part, Che in Bolivia, is about guess what. It contains too many indistinguishable battles and Che ministering to too many indistinguishable wounded.
When I realized this was supposed to be an "epic" (I never knew *anything* but the title before it started), I naturally thought of the greatest epic of them all, David Lean's Lawrence of Arabia. More of that later.
Not to be a racist, but aside from what I've already mentioned is the fact that there are too many characters who are, well, indistinguishable -- unknown Hispanic actors who look alike, especially considering they all wear "Che" beards and all wear Che fatigues. This results in the viewer not being able to identify with anyone other than Che, Benicio del Toro (even Fidel has a very minor role). While del Toro's terrific, think of "Lawrence" with Peter O'Toole as the only discernible character: no Alec Guinness, no Omar Sharif, no Anthony Quinn, etc. You get the idea.
Because the other characters are interchangeable, this results in a loss of reference. When top aides of Che are killed, you feel no remorse since you don't know who they are. Even when Che is killed (I don't think that's a spoiler), there's no empathy from the audience -- he's just killed.
He's too one-dimensional to relate to as a human being. Aside from being a revolutionary and second only to Jesus in moral rectitude, the only thing we learn about Che is that he's married with five children (he tells another character that near the end). What was his motivation? A complete enigma.
Maybe Soderbergh is purposely aping Lean. Like Soderbergh's Che, Lean never lets us know anything about Lawrence, the mystery man of Arabia. But at least Lawrence had a friend (Sharif) and associates (Guinness, Quinn). He was as courageous as he was insecure -- i.e., had human qualities. Che is like a machine, about as warm as The Terminator.
Earlier this year there was another war epic, Mongol. Che makes Mongol look like It's a Wonderful Life.