I personally have no problem at all with a program not totally resolving. Yes, the listeners might feel a little odd at the end, but they will think about it more.
Seems like it would be traditional to "resolve," but if it is intentionally NOT done, I think it can be just as, if not more, powerful. To me, it is not a problem to completely be absorbed in stuff like "Styx" it has a purpose, and it gets the listeners to brood. You may want to make sure the audience understands that this is not supposed to be like the 1812 overture or anything like that, but give some backround on the piece to prep them.
And besides, Styx is still on my playlist... I'm listening to it right now!
RnB