FFXIII is very linear.. that's my only complaint Sazh is bloody useless until you get his unique move, despite him being my favorite character...
My team lineup was Fang/Vanille/Hope and I used mainly Com/Rav/Rav, Sen/Med/Med, and Sab/Sab/Syn.
I believe after grinding my ass off I finally managed to beat the game at 50 hours play time.
If you think Odin was a bitch wait until you fight Hecatoncheir (Vanille's Eidolon). If you're not prepared for it, you're going to get raped!
protip for final boss: Sab/Sab/Syn works wonders.
..I also don't see why you have beef with paradigms, if you're getting hurt, pound on a monster with your Com to slow depletion of the chain gauge, then switch to Med/Med/Med or Com/Med/Med or something. Healing shouldn't take more than 10 seconds.