Sorcadin leveling question, 5/5 or 6/4?

[Corran]

As for Extra Attack, you can get around it via Feats (PAM)/Quicken Spell (Booming Blade). It's less of a big deal than it appears to be on first sight really.

Extra attack is useful for when you want to go nova, as it allows you two chances to smite without having to spend sorcery points (you can always spend sorcery points for quickening a weapon cantrip, but meh...). PAM is a poor pick for sorcadins.

Edit:
@OP: Skip PAM, you want your bonus action available for when you crit (GWM) or more likely for when you want to quicken a spell (most likely a buff spell during the 1st round of combat, probably a blast spell mid combat -or spiritual weapon since you are going ds for sorc origin). The spells you will most likely want to rely upon with your concentration (since you are a GWM), are bless (quickened), haste (quickened or twinned depending on allies) and greater invisibility (quickened or twinned, again depending on allies). Twinned haste is the best option in a void, but (quickened bless) will probably be your best option when fighting dangerous enemies (greater invisibility is hard to rate, as it depends exclusively on your party; ie do you have a melee rogue, do you need to tank enemies, etc). The bonus from aura of protection is not enough IMO. You need resilient con. So I'd start human and I would aim for GWM, resilient con and +2 STR when I am paladin6/sorc4 (besides, necrotic shroud uses an action, and GWM builds don't make the most out of powers that take actions away from their GWM'ing).