Yes it is not possible to have different strings in different ReportViewer instances and this is by design. As far as the accessibility and usability are considered, it is a poor practice to have different names for similar things. Anyway if there is a good reason and valid real-world scenario where this would come handy, we can reconsider our decision and look for a better solution.
The localizable properties approach allows you to localize only one report viewer at a time. In case your application utilizes more than one report viewer (which is a common scenario), you have to translate all resource for all report viewers separately. We consider this limitation as a serious disadvantage, which makes us believe that we have chosen the right approach.
The other approach that David suggested is very similar to the RESX one, since the RESX file contains exactly the same name/value collection he talks about, but in XML format.
In order to find the best solution for localizing the report viewers' resources I am kindly asking you guys to use this forum thread to summarize all common pitfalls and problems you are experiencing with the current implementation. We will review all of them and get back to you with our opinion on the matter.
Thanks for the involvement!
All the best,
the Telerik team