Im working on something not quite the same thing but that deal with all this, and being able to ship with a web rendering engine and not using whatever its on the system is actually better giving all the power, bindings, compromise you can make that you are unable when you can only deal with a abstract wrapper to every web rendering engine out there.
Lower memory footprint but with much less features and a generic "no sir, cant do such a thing.." as a answer to users that will need important features to ship applications with this.