1.) Alias only had 5 seasons and the 5th was stopped halfway through, then came back to wrap up the series(and season 5 wasn't that bad until they knew it would be cancelled).
2.) Seasons 1-3 were good, the first two were the strongest, but season 3 was solid.
3.) JJ Abrams wasn't writing Season 4 or 5 due to Lost and other works.
4.) JJ is still the shit.