One of the points raised in the OP was a need to improve public transport.
Some may disagree, and I am glad to see a long time resident of the capital agrees in the related thread, but the extension of Line 2B of the Metro and the subsequent extensions plus the cable car connections will prove to be an excellent investment in the capital where almost one third of the population resides.
There is also a move to improve public transport corridors and planned elimination of public taxis on some routes.
For those that are on the ground it is clear that some sindicos working some of the corridors with public taxis are improving their fleet. Independecia has a fleet of relatively new Kias and the same applies on other corridors such as Nunez, Sarasota and Luperon. Sadly some of the old fleet abound and a pass by km 9 on Duarte is a hit miss affair trying to ensure those pieces of rust don't clip you.
Changing the duties will not happen. There are high import duties throughout the Caribbean and the cars in DR are valued accordingly so politically it would be chaos. Changing rules on importing second hand cars could happen.....there are too many imports of questionable quality.
The key to improving the quality of vehicles plying the roads has to lie with a reintroduction of the annual revista. But that needs suitable testing centres first and by all accounts that is what is happening with test centres being identified. How good they will be and how adverse to a propina is another matter. After all in a country with poor uptake on timely relicensing and low levels of those insurance and over reliance on imports of questionable heritage, all that matters is getting from A to B in most cases and Alpha Male syndrome in others.