Should I re-do my char on oblivion?

I made a Oblivion Character, and I chose very bad combinations in the beginning. He is now level 11 and has almost finished Shivering Isles + Champion rank in the arena + Mehrunes Razor + Wizard rank in the mages guild, and Slayer in the Dark Brotherhood. Should I re-do all this, only to change from Spellsword + Thief = Bad Combination? I know it's totally up to me, but I'd like your opinion. Thank you.