Bunker Pillar, like 100% of Isolde's skillset, is -magic-, for starters. Don't see how LightSword helps against that bullshit. For speed debuffing, Isolde is vulnerable to MK's defense down debuff, but she immunes Slow, and things can immune or resist debuffs in SF unless I'm horribly mistaken - so, YMMV on that. Psychic Prison is also not a great idea against timed cards - Ancient Secret has three spells being cast, I'd only see that working against one, and multihitting/timed cards lulz pretty bad against Shadow Servant to boot.
EDIT: I -was- considering Blue as having skillset shenanigans and better than lololol JP. Problem is all his damage is inferior to BoundShot, and as far as I can see, only chipping and plowing with BoundShot even remotely gives him a chance, since otherwise he's ingloriously ramming into Isolde's near 3x PC HP mdur and he's in deep as soon as Isolde starts dropping Grand Gazes and their odds of inflicting the horrors of MK Slow along with damage that chips away at him no strings attached. EDIT: Wait, he immunes Grand Gaze! But man, that does his durability no good and she can still Silence -and- damage him. And Ancient Secret coming up, as before, spells doom even before Bunker Pillar insanity.