The RAM was a six speed manual, the Dakota probably a four speed. But these new 6 speed autos are just adding overdrive gears. If you don't like the annoying down shift to 5, just run in 5 instead of D. I run my WK2 routinely in 5 to reduce the amount of annoying shifting. Doesn't affect gas mileage. The only time I use D is cruising out on the highway. A much more satisfying experience. For the V6, try running in 4th instead of D, which is the direct 1:1 ratio.
You can think of putting the transmission in 5 (if you have a 6 speed) as the same as changing the axle ratio.
Changing the axle ratio for the street makes sense if the ratio you want is not provided either on the low or high end of the gear box.
For example, I'm not sure what the top trans gear ratio of your RAM is, but if its the same as the WK2 V8, its top gear is 0.67 when combined with your 3.82 ideal rear end ratio, that is 2.56 overall, the V6 automatic top gear ratio is 0.83 and when combined with your 3.06 axle.. guess what... thats 2.54 overall, near identical to your ideal final drive.. you are already there