I would like to point that paladin SPD cap is 25, not 26, just like those of Falcon Knight, only 2 points higher than Dragon Knight.
Yet Sheeda will be able to double most of the enemies even with 23 speed, and +2 STR and +3 DEF of the DK compared to the FK are literally what she is crying for since the beginning of the game.
Also the enemies vulnerable to her Winged Spear (that makes her primary targets) are usually low in the speed department.
If what makes Sheeda good is the Winged Spear, why use her against enemies that are not vulnerable?
The chance to get a couple of extra HP is just an extra bonus.
But this also means that swords for Sheeda are an inferior choice compared to axes (she don't needs accuracy, but extra might and swords will not be on par with axes until her skill will reach level A, that is higly unlikely and/or very late in the game).