When trying to use WSMModelData[model,"Summary"] the expression takes way to long or hangs (I haven't seen an output)
It runs a validation of the model, which can take a long time if the model is complicated to validate. This is sometimes the case for Media models.
The same is true of other WMModelData properties like OutputVariables. ParameterValues works but is slow.
This has to do most of the processing that building the model does, so it also does a lot of work.
But I wouldn't expect that to prevent WSMModelData from returning some of the properties of the model.
It shouldn't if the model is valid. If you would like to share the model, we could have a look to see if there is a bug.