the yaml files (and to some degree even their php conterparts) need to loaded and parsed for extending presets, layouts and extends.
with more and more people using lots of blocks 30+ in a single setup this creates a heavy load to initialize.
what if the parsed endresult of a pages blueprint is stored as an optimized php file fully unrolled? with proper code these php should be recognized by standard php cache libs like apcu, cached and thus be loaded faster.
the cache should be optional like the pages cache and clear itself if any blueprint file was modified.
i thinks its at least worth a try.