instead of the US market only six cylinder version. In current market I bet:
1. You save money for not making a special US version

2. You will sell more 2.0 and TDI here anyway

I would buy either...but will not get the V6.

Jetta is light enough to use the 2.0 TDI with no urea injection. The Tiguan isn't that's why there will be no Tiguan TDI.
Q5 would be much to heavy for the 2.0, the 3.0 should be able to pass emissions without urea injection.

In Germany/Europe they only offer a 2.0 TFSI Quattro non-Diesel engine:

0..60mph: 7.2 sec
23/33mpg city/highway EEC
28mpg combined EEC
Reduce about 20% to get EPA test numbers (which is about 22mpg combined).

Fast enough and good fuel economy I'd say.
So far only the A4/TT in the US is offered with a 2.0TFSI engine. Perhaps because they can make more profit and 2nd competitors typically have bigger engines as well?

Q5/A5/A6 with a 2.0 TFSI engine is still fairly fast and would be much cheaper. I'd love if Audi offered these here as well.