I've noticed this too, with NOK-EUR-USD. The NOK went down compared to the EUR because of the collapse in oil prices (may be changing back). But in the same period the EUR lost ground to the USD. To me, XBT isn't looking that bad...imagine how it would look if you were holding BRL!!!
I agree that it would be interesting to measure Bitcoin versus a basket of currencies and commodities. But the USD is still the biggest and most influential currency out there. Even in the terrible state of the US economy, investors flee to the USD at any sign of trouble. USD zone is 60% of world GDP (http://www.economist.com/news/special-report/21668717-america-centre-global-monetary-disorder-thrills-and-spills). The USD is the world reserve currency that every central bank wants as a large chunk of their reserves. The USD is easily recognizable and still trusted throughout the world. Moreover, the USD has an offshore market of bonds created outside the US borders worth more than half of the US GDP.
We just simply can't get around the fact that the USD is the outsized currency that is relevant to everything financial for the moment.
To me, I rarely look at prices in Bitcoin because I rarely buy stuff, and when I do, I usually use fiat cash that I have long since withdrawn from my bank account to prevent them from lending it out to other people who are using it for God knows what and to lower the risk of not getting it back at all.
Bitcoin has another value to me than the dollar value – it has a value in freedom that is far far higher...and that is why I consider it a great buy opportunity every time I have spare fiat around.