Yes, you were much worse before if you mean as a DART debater. People say you got worse when you came here and 'improved rapidly' but it's that you got slightly rusty and had gotten wiser but clumsy vs the norm here.
In DDO you could easily expect many noobs to accept debates, not just instigate them, so noobsniping was a matter of actively doing whatever you wanted and if a hard debater showed up you can just 'wing it' and not care too much about the loss. What you realised early on is that you can't handle the 11-on-the-go chain debate style you had at DDO in your hyper phases.
You also began to realise that voters here pay more attention to actual arguments-vs-rebuttals interaction (whether correctly understanding them or not) whereas on DDO eloquence mattered much more than logic, voters tended to get away with sloppy votes that just showed they got the 'gist'. This led to you learning to focus on the logic more than eloquence which is a correct adaptation to this site's environment and norms.
You never got worse and then 'rapidly got better' you just had a skillset coming here that was good enough for DDO grinding but bad for DART grinding.