I think more and more people will start turning to newer BMWs especially since they have become so cheap in comparison to a good e30. This applys mainly to daily cars. There is something refreshing about driving a car without rust issues, a thirsty and needing(repair) m20 engine. The benefits of cruise, air con and airbags are also a positive for some.
Would I go back to a daily e30?
For me it is a No, as nice as mine was to drive, you had to be on the edge of your seat when you drove it in the wet. It didn't have air con, it didn't have traction control, it didn't have ABS etc. If you do mega mileage in one, even the very good sport seats become uncomfortable. I have the 205 if I want to be obtuse/offensive/uncomfortable and want to get somewhere quick!
Newer BMW's you could waft around and do mega mileage with more creature comforts for less money. If the 530D was reliable, I think that is the car to buy.
The one that will tempt me back in later life is an e30 m3 for the weekends I think.
just picked up some of those wheels for my Touring 
