Hi Mauidj,
any time I have heard a Oracle in a set-up I've always really enjoyed listening finding the system to be very musical, listen for hours. The eye candy look is very unique and appealing also, you being a happy owner why not just go for the Delphi VI as you mentioned and enjoy for another 30 YEARS or more.
It's really going to come down to your own preference but if you can't demo in your own set-up and are just relying on others comments it's going to be a coin toss, the other tables you refer to will offer a different flavour sonic wise but ....
I also believe the rest of your set-up is important because of the impact.
When I was looking and heard many different tables I always seemed to gravitate to an Oracle and a few German made non suspension, I found that the non suspension offered a different foundation body TEXTURE to the music which I liked so that was the route I choise. There are so many table designs available and in the end will offer a different flavour but you still have your arm, cart "set-up" etc. that will all have a impact on your end result.
If it was me and I truly enjoyed a pce for 30 YEARS the only way I would even contemplate go to a whole new design would be to have what ever peaked my interest in my system for a while and live with it, quick listens might be exciting but that's it.
Good luck and have fun!