Along these lines I would suggest updating Yii's marketing tagline to this:
"Yii is a high-performance component-based PHP framework best for practical developers to build high traffic web applications."
Note the "practical developer" reference, I studied Makaroff's slides on Yii2 and the "practical" word kept coming to signal that Yii is not trying to generate consulting business by code complexity (ie Symfony and Zend).
And if someone thinks that Web Speed is only a server-level thing that exceeds the framework and the application, here's an excerpt of Google's best practices at the Application level:
Use a single connection - it’s better for SPDY performance and for the internet to use as few connections as possible. For SPDY, this will result in better packing of data into packets, better header compression, less connection state, fewer handshakes, etc. It improves TCP behavior across the internet and reduces bufferbloat. Interacts better with NATs as well as it requires less state.
Don’t shard hostnames - This is a hack used by web apps to work around browser parallelism limits. For all the reasons that we suggest using a single connection, hostname sharding is suboptimal when you can use SPDY instead. Furthermore, hostname sharding requires extra DNS queries and complicates web apps due to using multiple origins.
Use server push instead of inlining - This is a hack used by web apps to reduce RTTs. Inlining reduces the cacheability of web pages and may increase web page sizes due to base64 encoding. Instead, the server can just push the content.
Use request prioritization - Clients can advise the server on relative priorities for resources. Some basic heuristics which clients should all do generally is to make sure that html > js, css > *.
Use reasonable SPDY frame sizes - Although the spec allows for large frames, it is often desirable to use smaller frames, because this allows for better interleaving of frames from different streams.
Don't use CSS sprites with external stylesheets - Resources in external stylesheets are obviously only discovered after the external stylesheet has been downloaded, and only once the rule matches an element. The advantage they provide of reducing HTTP requests is unnecessary with SPDY due to its multiplexing. Therefore, CSS sprites just make it slower.
If Yii is a framework for building *web* applications, then it should also help both developers and project owners cope with web application success, Yii is not a front for generating consulting business or a new toy for web artisans, Yii is a serious tool for building web applications and therefore should come out of the box prepared to face the consequences of success: a ton of traffic.