I'm guessing you're a woman that has either an impairment with your vision/brain or owned a different version of Dragon Age 2 than the one I'm familiar with and likely lack the knowledge of how combat in general works (images4.wikia.nocookie.net/__c… this is the Isabela I'm familiar with. as I hope you're able to see she would be able to run in that without it falling apart) you are correct on the armor's 'usefulness' and the fact that it was made for appeal, but to say that it would not allow her to feel lighter and more mobile would be incorrect. armor for a rogue or an agile fighter like Isabela would be more of a hindrance than a help. armor is made to protect those that lack the stamina and skill dodge, parry or counter an attack like a rogue, martial artist, or just plain badass of a fighter. besides, isabela likely has little problem running around naked in combat if you've played the the legacy DLC (look here youtu.be/X0z5NE5V-DA?t=2m7s). also look at some of the characters in mass effect; Jack in ME2 was topless (unless you had her AAP DLC. the only thing covering her were belts and biotic barriers; Miranda was in a catsuit (again, unless you had her AAP DLC). in medieval combat a lady warrior exposing some of her skin can actually work to her advantage when fighting against other men and it can kind of work in the mass effect universe too, because a moments distraction can bring their death.
on the subject of a more accurate crossover (which is pointless to discuss with you, because the artist already made it clear that he isn't changing it and if I don't like it I should make my own). I was basically saying that Isabela was a pirate not a mercenary and that she should have lighter armor and have different weapons, the weapons Isabela used are like someone duel-wielding sidearms, because daggers/knives were secondary weapons in medieval times much like pistols and some SMGs are backups to a soldiers main weapon (rifle, shotgun, etc.). the Omni-blades are more like a hidden emergency blade that you use when primary and secondary weapons are unavailable for some reason.
your missing a few important points (likely due to language barriers and the fact that I might have neglected to mention certain things)
1) Isabela has no problem being naked (I'm not sure if the Russian version of her character canon differs from the American version, but she is very promiscuous in the version I'm familiar with). the only problem she has being naked in a fight is that she would only have 3 daggers (I'm not sure whether you were able to view that link in the previous message but it was stated there). She also states why she doesn't wear pants in the legacy DLC
2) Nearly all the rogues in DA2, with the exception of Hawke, wear that armor like that because they are nowhere near the badass that Isabela is and they're nowhere near ready to bang something like she is.
3) I tried to say that the advantage of outfits like hers is an extremely temporary one and likely able to be useless the next round of fighting but certain foes it can shake there resolve slightly which may or may not work in her favor.
I meant someone with no legs and no tools/physical conditioning to help him/her achieve the necessary speed to win (high-end/high-powered wheelchair).
I probably should have said "like asking someone quadriplegic or paraplegic to win a race against opponents that have full use of there limbs" so that would remove all confusion.