Rqt_reconfigure should be updated to use async calls to the parameter service(s). First, it is (incorrectly) assuming that every node supports the parameter services. However, if one creates a parameter client for a node which doesn't provide the corresponding services and then invoke it, the synchronous call will hang. Next, even if a node does support the parameter services, the node may not be spinning (for example, a node created just to make a service call). In this latter case, using a synchronous call to a parameter service will also hang the calling app.
Rqt_reconfigure should be updated to use async calls to the parameter service(s). First, it is (incorrectly) assuming that every node supports the parameter services. However, if one creates a parameter client for a node which doesn't provide the corresponding services and then invoke it, the synchronous call will hang. Next, even if a node does support the parameter services, the node may not be spinning (for example, a node created just to make a service call). In this latter case, using a synchronous call to a parameter service will also hang the calling app.