The damage numbers you are referencing seem t be suggesting that the champion or the hexblade will be doing a point less than the there, that's j\so incorrect it doesn't relly matter which. Here's the math.
Champion will be doing 1d10+5+1+10 (5.5+5*+1+10=26.5) for each attack. EB from the hexblade will be doing 1d10+5 (5.5+5=10.5). They each get to attack the same number of times aside from the almost unplayed 17-19 level range. The hexblade is doing way more than a "point" less damage. The champion can miss 2 out of every 3 attacks and still outdamage the hexblade with EV if it's missing an average of even a single attack every 3. From 1-4 it's still true but needs different mods. On the bolded but, look back at
@Flamestrike's
post.... the champion has both feats and a +1 weapon of each. Ranged attacks with a bow in melee & ranged spell attacks with EB in melee both suffer the same disadvantage so it would be silly to throw the comparison by adding it to one but not the other.
To be clear I said
"you are probably looking at 2 points extra damage per attack effectively, compared to someone using the same weapon without the feats". Here is the actual numbers to back that up:
Comparison at 4th level:
A 4th level Champion with 16 strength and GWM wielding a greatsword will average 6.7 DPR against a 15AC foe if he takes +10 damage and will average 6.2 DPR if he does not take +10 damage
A 4th level Champion with an 18 strength and no GWM and a greatsword will average 7.2 DPR against a 15AC foe.
A 4th level AB blastlock with a 18 Charisma will average 6.0 DPR against a 15AC foe
Difference:
GWM is 1 point worse than a comparable fighter and 0.7 points better than a blaster warlock.
Comparison at 6th level:
A 6th level Champion with 18 strength and GWM wielding a greatsword will average 9.1 DPA (Damage Per Attack) against a 15AC foe if he takes +10 damage and will average 7.9 DPA if he does not take +10 damage.
A 6th level Champion with an 20 strength and no GWM and a greatsword will average 9.1 DPA against a 15AC foe.
A 6th level AB blastlock with a 18 Charisma will average 6.5 Damage Per Ray against a 15AC foe.
Difference:
GWM no difference for a comparable fighter, 2.6 damage per attack better than a blaster warlock.
Comparison at 8th level:
A 8th level Champion with 20 strength and GWM wielding a greatsword will average 10.6 DPA against a 15AC foe if he takes +10 damage and will average 9.1 DPA if he does not take +10 damage.
A 8th level Champion with an 20 strength and no GWM and a greatsword will average 9.1DPA against a 15AC foe.
A 8th level AB blastlock with a 20 Charisma will average 7.6 Damage Per Ray against a 15 AC foe.
Difference:
GWM 1.5 points better than a comparable fighter and 3 points better than a blaster
Comparison at 11th level
A 8th level Champion with 20 strength and GWM wielding a greatsword will average 11.7 DPA against a 15AC foe if he takes +10 damage and will average 9.7 DPA if he does not take +10 damage.
A 8th level Champion with an 20 strength and no GWM and a greatsword will average 9.7 DPA against a 15AC foe.
A 6th level AB blastlock with a 20 Charisma will average 8.1 Damage Per Ray against a 15 AC foe.
Difference:
GWM 2 points better than comparable fighter and 3.6 points per attack better than a blaster
Note: That includes the Champion bonus for critical hits, it does NOT include the GWM bonus action attack on a critical hit/kill, any fighting style adjustment or Hex. That is also against a 15AC foe, raising the AC will reduce those differences and turn them upside down at very high levels. The example I gave above is for a greatsword.