The world of smart font rendering has matured and the dominant processing model in the industry is that based around OpenType. This means that segments will tend to be smaller single-attributed things. The bidi algorithm will already have been run and line breaking is done by the application. The upshot of this is that the current Graphite engine is optimised for the wrong use cases and there is a need for a new lighter weight engine that fits better into OpenType-based applications. This is not to detract from the high quality that the current graphite engine is. This is not just about writing a faster engine but about fitting better with the world into which Graphite needs to fit.