I have a Mage with warrior back up style and I would like a sneak stealth character, but can I change my character and keep my quest progress so far or would I have to restart from the start and could I keep my progress from the other setup? I dont think I have enough perks to do both. Also if I maxed out the armour cap over 1000 using daedric and potions would using the right side of the heavy armour tree be pointless, all the 25% armour bonuses?

EDIT: Scratch that. I reread and I think I understand now. And no, you can't respec your spellsword to have sneak perks/qualities. You need a new character for that

Armor cap is 567, and that gives you 80% damage reduction. Anything more than that does not help you. A lot of smithing players do not take more than one base armor perk because it's not necessary with smithing and alchemy.

If you are on a PC, you can change around your perk distribution with console. If you are on a PS3 or Xbox, you would have to start a new character. But I think building a new character is a lot of fun and you get to discover new things even if you played the game before.

Skyrim is my first RPG, im more of a FPS player, BF, Crysis series, Halo etc, well I played Runescape for a while if that counts. Also could I keep my old progress though if I started a new one? and a fail all those youtube vids with people showing how to get a 1000+ armour rating are pointless, and the perks as well if you can get to the cap without them.

just make a save on one character and make a new game...