WildFly boms are completely separate from WildFly main build.
boms are meant for users to have common set of server provided APIs / components available to them at build time.
As such we don't provide all components WildFly bundles in boms, as many(most) of those jars are considered server private and not meant be used by users directly.
Said all that, I do agree that stuff like slf4j should be declared in our boms.
I will fix that right away and do new release of 10.x bom that will include it.
WildFly boms 10.0.1.Final ware released yesterday that include also slf4j and few other useful deps.