I drive a 2.5, and I wouldn't want to go down to a 2.0. The extra torque, especially at low rpm, is something I would miss too much. That would be especially relevant with oversize tires. Of course, if you've never tried the 2.5 , you might be quite satisfied with the 2.0.
Judging by the posts here, you are right about reliability.
I think, under normal driving, the 2.5 does 2 to 3 mpg less. Then there's two extra plugs, etc. You pay for your pleasures.