First off: I completely agree. I do quite a bit of work with Web Services and ServiceNow, and using Java and/Or .Net is quite different than using a scripted language (I usually use Perl for scripts). The inherent issue comes into the fact that a WSDL should not be changing that often, especially in production. The idea in Java and .Net is that you get these stub classes to get compile time error checking.
If your currently in a Ph1 and haven't deployed Prod yet, then you should really look into how often that WSDL will be changing. Then make your decision from there on which technology to use. The nice thing is that even if the WSDL changes, posting data to the instance - almost all of the fields are optional. So if a new field is added it's not a big deal. The issue comes in when data is returned (most of the time) because many times java and .net will throw an exception if the returned XML is not in the structure it is expecting.
One thing that many people do is setup Modules as CI's in the CMDB and maintain their ServiceNow instance through the Change Request module. That way your java application will be a downstream CI to whatever module/table you are querying, and when a CR is put in to modify that table, it will be known immediately that there will be an impact on your internal application as well.
Unfortunately you are right though, that is a trade off with the different languages and from my experience there is very little we can do to change that.
One thing I forgot to add, another option for you is to use the JSON service instead. That will allow you to make raw requests to the SNC instance then use a JSON parser to parse that data for you "on the fly" so to speak. It takes away the compile time checking but also takes away many of the flaws of the SOAP system.