Currently in the wsdl2rest wizard, we rely on the text of specific warning messages provided by the validators to indicate whether a particular warning is more important than another. For example if a message is prefaced by "Caution:" we (in the wizard's "canFinish()" method) indicate that the user must still go to the 2nd page before clicking Finish. This ensures that they see the warnings before blindly clicking Finish without knowing about them.
It's a state somewhere between an error and a warning that we want to convey, and the Eclipse wizard framework does not have a state we can use to handle this. The use of the text of the message was a low-tech solution.
According to Aurelien, it might worth setting a specific boolean flag or setting something on the wizard page databinding to handle this vs. relying on a string that may or may not be localized at some point in the future.