The DA and 1v1s in general with a same plane setup are by far the best way to improve as a pilot in AH in my opinion. The fight/time ratio is unmatched and the skills you pick up in there will be invaluable in the MA. Obviously there are elements of an MA environment that the DA cannot reproduce, but having a solid foundation in duels and dogfighting will get you pretty far.
QFT
The problem with a ladder is...
1. Agreement on the rules(someone has to take charge and they need some backing from the community)
2. Participation, a lot say they want to participate but then miss their duels so it ends up being a bunch of forfeits which is no fun for anyone.
3. Lack of a judge/witness during a contest. Many have had similar turd experiences in the DA an FM2 pilot went to the DA with me once and was diving in prior to icon range to have an E advantage....did it again with someone watching and all the sudden he didn't know what to do

(Someone cheating/griefing in the DA should be flattering...means their afraid of your Skillz)
The best way IMO is to have a dueling ladder "night" where someone watches all the duels and the rules are set prior to...no exceptions....changes can be made later if the majority of participants want the change....Kind of like KOTH (DISCLAIMER: KOTH is not a 1v1 event, it is better classified as a Battle Royal...last man standing wins but at the same time there are a lot of 1v1s which happen at different E states so you have to have SA and knowledge of ACM to win....still have yet to see a pilot win a KOTH who I didn't think couldn't pull it out...a lot of people are afraid to come out for KOTH because they believe it has a lot of ego but truly it gets squashed fast)