While there is slight increase in overall damage with Shield Swipe, as a tank I'm far more interested in threat/enmity generation. After converting those same figures into threat...
Consider 12 turns (4 Halone combos).
100 > 200 > 260 > 100 > 200 > 260 > 100 > 200 > 260 > 100 > 200 > 260
2240 potency.
100>600>1300>100>600>1300>100>600>1300>100>600>1300>
=> 8000 enmity

12 turns with Shield Swipe in every second attack.
100 > 200 > 230 > 260 > 100 > 230 > 200 > 260 > 230 > 100 -> 200 > 230
2340 potency.
100>600>230>100>600>230>100>600>230>100>600>230>
=>3720 enmity

Shield Swipe once every attack.
100 > 230 > 200 > 230 > 260 > 230 > 100 > 230 > 200 > 230 > 260 > 230
2500 potency.
100>230>600>230>1300>230>100>230>600>230>1300>230
=>5380 enmity