Well my point was more towards how these things are supposed to be difficult to counter. Its not just about level 6 ganking powerspikes, but also reliable ways to stop hyper slippery champions like Vayne and Yasuo. If you want an item to stop her buy a GA or a Zhonya's.
And trust me, I hate Vi a lot (When I discovered GP's oranges didn't save me from her, I got so pissed lol), but I can tell that design-wise, some CC just shouldn't be avoidable without a price (which is freezing for two seconds with a Zhonya's)