The more optional deps the Weld subsystem module has, the better as it helps allow slimmer runtimes.
1) org.jboss.as.security – classes from this module (SimpleSecurityManager[Service] should only be loaded if the org.wildfly.legacy-security capability is present, so this dep can be optional.
2) org.picketbox – AFAICT these are only used via org.jboss.weld.security.spi.SecurityServices impl methods that are never called. And it seems like they wouldn't be expected to work without the org.wildfly.legacy-security capability being present anyway. So I believe this dep can be optional.
(Edited to comment out the second point since a) the SecurityServices methods are indeed called and b) it's not obvious they'd never be expected to be called without the security subsystem. Probably wouldn't work right but it's too complex a task to validate that.)