I'm not sure why folks get so bent over what a car should have...regardless of the layout chosen (FWD, RWD, or AWD), the only pertinent question is whether or not it works for that particular vehicle.
The bigest RWD car makers in Europe are MB, BMW and Porsche, heck even Ferrari, Aston and Pagani outsell in RWD cars sold brands like Fiat, VW, Opel, Ford, since the later abandoned RWD.
Also big FWD cars usually aren't fun at all, despite that small ones can be or are/were.
As for what makes a racing series more exciting? That depends on the individual, as well. The RWD, V8 combo in NASCAR does little for me, but I love to watch other series with V8s (CART, F1, ALMS, etc.).
Don't like NASCAR either and I like the rest but I hate it that F1 went to V8 from V10s. The new V8 give less power - torque and are burning MORE fuel. So much for cost cutting.
Back to the original topic...do I think BMW should race in DTM? That's up to them, really.
My problem with DTM is that there's only 2 manufacturers invloved and it's no longer worthy of the Touring name.
Touring in the old days meant putting a safety cage, and moding a car to some extent to improve performance/bring it to FIA regulations and then go racing.
DTM nowadays is mostly spec series like NASCAR.
This is also a problem with the WTCC but it's not a bad as DTM and/or NASCAR.
BMW's sales are not predicated on winning on a track...
That's hardly the case for anyone.
I'd wager that a lot of BMW owners don't follow motorsport, at all.
With that I don't agree. BMW onwers, well some, in some countries, were, are
and will continue to be involved in racing legal or not. That's been the case since the 1930s. That also applies to Porsche too. Ofcorse the costumers base has expanted lately.
Motor-sport activities of a manufacturers/brand are not restricted to the Works entries, but there are also partners and privateers.