Callahan ultimately ended up not being the right hire. Pelini ultimately ended up not being the right hire, even though he got us to a few conference championship games and won a few bowl games. Will Riley end up being the right hire? Who knows, but 5 games in is far too early to tell.
You know what? The start Riley's had isn't too far off from the start Bo had in 2008. And let's not talk about talent left by the previous coaching staff, let's just assume they're equal: you'll hear people say that Cally left no talent and that Pelini left a lot of talent and vice versa, so let's just say they're equal. In 2008, Bo had wins over Western Michigan (47-24), San Jose State (35-12), New Mexico State (38-7), before losing to Virginia Tech (35-30) and Missouri (52-17).
ESPN likes to track win probability of teams at various points during the game. Against BYU, up 28-27 with :01, Nebraska had a 98.5% chance of winning. Nebraska lost. Against Illinois, up 13-7 on 3rd and 7, Nebraska had a 99.5% chance of winning. Nebraska lost. We had a 98% of being 4-1 right now, and we've just happened to wind up in the 2% this time. Even though one of the games was really the result of a bad playcall, let's just assume that that playcall was simply unlucky and a matter of chance (who knows, maybe Tommy wasn't supposed to throw the ball). We won't always wind up in that 2% area, it's just probabilistically unlikely.