I see where you are coming from but what DSS V6 will have in the future releases the DSS V5 could not do. Similar to Microsoft products,... try to upgrade from WSS 2003 to 2008, you will be amazed and the cost and not to mention the upgrade issues. I purchased a Windows XP many moons ago and then Vista came out. I asked them to give me this for free as if I waited 3 weeks more I could have received it and never got a reply..... but that is MS.
With DSS V6 we will be able to much more then DSS V5 and DSS V6 has been in development for 2 years now. Under the hood is allot more development then the DSS V5. Just like MS (but with free support), it is part of the sw evolution.