The Flex-1500 is really a neat radio, and as is with the present release of PowerSDR is a great value.
The discontinued Flex-5000 & Flex-3000 radios as second hand purchases, again using the latest PowerSDR version, are great performance values in SDR when based on keeping investment low.
It is doubtful that any new features will be coded into PowerSDR unless done by a 3rd party programmer or as a "fork" where use of the non-public domain parts of PowerSDR have been secured.
Lacking such developments best guess and only reasonable assumption is what you have is what it will be.
Personally I wouldn't count on newer versions of Windows remaining stable with the Flex-1500/3000/5000 and PowerSDR over the next ten years. Mostly the drivers needing to match/work and the slow fade in availability of the IEEE 1394 Firewire port for the 3000/5000 interconnect are the problems one can see getting in the way.
Buying into a Flex-1500 and PowerSDR 2.7.2 here and now with an expectation of some new big launch of additional features has to be frustrating, as FlexRadio Systems has never even hinted there was any major upgrade in the works.
While a major upgrade may be wishful thinking, there is no denying the Flex-1500 with PowerSDR 2.7.2 is a lot of fun and can really knock out some contacts. For the price point the combination has a lot to recommend itself over.
One also wonders if somebody might hardware hack a Flex-1500 along the way with a custom rolling of PowerSDR adding a lot to the combination all told - but again just wishing for it doesn't mean it is at all likely to happen. I kind of think the energy to do so would be better spent on a SmartSDR add-in package than futzing with custom PowerSDR versions.
Having siad that, I came across dl2tw website where he has had a play with it running visual studio 8 instead of the olde version 3 it was written in. But as they say, its time to dig in the heels and play.