- Pipelining would be pretty cool if it worked. There are a number of problems with it: * head of line blocking * transparent proxies that don't support pipelining properly * error detection - FIFO queuing: Why is the client in a better position to know in what order the page needs to be rendered than the server? Isn't the server the one that knows all the resources that need to be sent to the client? - Client initiated request: Yeah, server push is a complicated area. But there are some cases where server push is clearly superior. For example, data URI inlining ruins cacheability. It's better to server push an already cached resource that can be RST_STREAM'd than inline a resource and make it larger and uncacheable. - While we'd like to get rid of headers as much as possible, it's still impractical to completely eliminate headers like User-Agent. - SPDY does not force data compression, and optional data compression has been removed in draft spec 3.