What usage should Internet architecture focus on?

Internet architecture research aims to improve the infrastructure of the Internet, but with respect to what? I think most would say that we should meet the most common needs, both current and foreseen, but on thinking about what those needs are, it seems that even that is a difficult question.

Accesses to given services may be a good measure, but improving the network's ability to serve small content fast may harm services that transfer large amounts of data, such as video or possibly gaming. Well-intentioned efforts in enabling easier network research may cause difficulties for those pursuing network security. The ever-present problem of network architecture research is, then, the inherent alteration of the status quo for every endeavor, field, or application built on the current architecture. While we can (and, I think, should) try and minimize the impact that architecture changes would have on current usage, the fact of the matter is that to do anything very meaningful with such a fundamental change as architecture, adaptations will needed at every level of the current architecture. This may be why changes to the way we use the Internet happen incrementally - too much resistance to universally disruptive change. Testing issues make network architecture research difficult; implementation issues threaten to make it prohibitively impractical.