From JBIDE-10527 I see that the following keys are stored in application servers:

org.jboss.tools.openshift.express.internal.core.behaviour.ApplicationId="769fbce4ec324292938a7aca2d7cbb69"
org.jboss.tools.openshift.express.internal.core.behaviour.ApplicationName="app9"
org.jboss.tools.openshift.express.internal.core.behaviour.Domain="yourDomainHere"
org.jboss.tools.openshift.express.internal.core.behaviour.ExpressMode="publishSource"
org.jboss.tools.openshift.express.internal.core.behaviour.Username="username@example.com"
org.jboss.tools.openshift.express.internal.core.behaviour.binary.deployProject="app9"

Two problems here:
1) the use of internal package names as base of the key - why is this not just openshift.<key> used as user visible setting ? Only if its something truly jboss tools specific could I see a reason to use a packagename, but still then not use internal since this key by the fact being stored in users settings are public and non-internal.

2) I think the project it self should be where applicationid, domain and usernme should be stored so the only thing the server needs to keep track of is deployProject and expressmode (if that is at all relevant anymore?)

When creating servers you just then point to the project and get the info or select an application + project and the settings gets stored back on the project.

That could be stored in .settings and be made available for tooling outside AS server integration.