I cant agree wit You.
there are styles for k2store to support what it generates (the html code), and because this generated code is simple, so is the styling (without the styling all aditional elements would just look weird).
VirtueMart on the other hand generates completely different code, written specially for this purpose, and so the styling can me more advanced.
What isn my opinion most important - Yu cant style the html code that is just not there (k2 store), and rewriting k2store to generate more custom code is not our job.
I dont know if you are advanced frontend developer who knows html and css well and knows what I'm talking about. Its like changing tires in your car - sure they will give you better secutiry etc, but will not change the way your car looks entirely (k2store). You need to change entire car to see the difference (VirtueMrt).