I think PoSmedley covered it about as well as anyone....
There is a fundamental difference between such programs as Windowblinds [and other shell enhancements/and/or replacements] vs something, say, like Photoshop.
The latter, if not quite 'stable' within a Beta OS - crashes.....it means you can't draw something.
If something which interfaces between the OS Kernel and the user - crashes....the likelihood is you cannot continue to interact with the OS at all.
How often have you seen a system lock-up due to an un-responsive Explorer.exe? The OS shell has crashed and your computer will have "lights on but there's no-one home".
Most users are not going to be comfortable with killing the shell process and accessing the kernel direct ... or, alternatively.... a hard reset and losing whatever work/etc that was happening prior.
Microsoft [rightly] plays with all sorts of 'bits' of their Beta OS during this current phase of Win 7's development....and no-one here, OR at MS would be able to guarantee that system lockups, etc will not happen through any such 'deviations' of compatibility.
Stardock is being sensible holding back with any WB7 release as their only real commercial obligation would be to guarantee an on-going compatibility of WB with FINAL-Release Operating Systems....such as Vista, XP, and perhaps what are now 'legacy systems'.
Win 7 is not [currently] a commercial product that 'requires' support. If current [WB] users choose to experiment with Win 7 that is their choice, not Stardock's. If that means they have a product [WB] that they cannot subsequently/currently use on the new OS then that too is their choice. Arguably there is no difference were they to now be playing with a Mac OS and have no option to use WB....other than knowing that when they have an OS that they will be paying for...they will likewise have a WB that can be applied there-to.
This query/request/complaint is not new. As far as I can recall it has happened pretty much with every new OS beta/release as Microsoft Windows evolved with its GUI.
No-one here is saying 'shut up and wait'. They are saying 'please be patient'. I too have Win 7 [in Vmware] but do not have it skinned....I don't have the in-house WB7 either.... but I know that when Neil and the guys are happy/ready/ and confident that the final of Win 7 is to be no different to what is in the wild ...I'll get my 7 ....and so will you...;)