The +1 Courageous weapon gets +1 Will saves over the +2 Weapon. That is the only thing extra you are getting out of it.
That isn't correct. The second barb gains the following benefits that the first doesn't:+1 on _all_ attack rolls, whether with that weapon or another.
+1 on CMB rolls not utilizing the weapon.
+1 on CMD
+1 will saves
+1 on strength and con checks
+1 on fortitude and will saves
That's more than +1 to will saves. Whether it's balanced or not is another question, but don't sell it short when it has noticable benefits.
Also, if we compare a more beneficial scenario, that is more likely considering if you're a barbarian you aim for it:
12th level barbarian
Str 29 when raging (16 base +2 racial +3 level +4 belt +4 rage)
Con 18 when raging (14 base + 4 rage)
Has prebuffed with Heroism (wand charge is dirt cheap and lasts 40 minutes)
Has Adopted/Tusked racial traits
Normal attack routine is +23/+18/+13 (2d6+13) and +18 (1d4+4)
A +2 weapon will change the routine to:
+25/+20/+15 (2d6+15) and +18 (1d4+4) and will also give
+2 to any CMB checks with the specific weapon
A +1 courageous weapon will change attack routine to:
+26/+21/+16 (2d6+16) and +20 (1d4+5)
+1 to any CMB check, +2 to those with the specific weapon
+1 to all saves
+1 on various skillz and trickz
So yeah, with very low synergy it comes out just right ahead, and with decent synergy (not even a real investment) it comes out way ahead.