Yes I agree. A "cloud" implementation of a PDF reader would be bad in a whole different way. It is annoying to have to use the "cloud" term at all as it implies certain things beyond just being a distributed/decentralised cache of data and external processing power. Those are the things that make the cloud approach useful and its a shame some of that cannot be used in normal desktop applications.
[1]: I have nothing against clouds, -as long as they are not mandatory that is.