As you probably already know, Schema Explorer is implemented into The Welkin Suite IDE. This became available for you beginning from the Beta 0.30.7 version of the IDE.
You can use the context menu of an object to create a SOQL query.
Additionally, the advanced SOQL executor with the list of queryable objects with their fields and child relationships which can be used for creating your query is implemented in The Welkin Suite for Mac, and soon this functionality will be available for you in TWS for Windows.
If you have any new suggestions, please share them with us.