...and a conviction would improve things? Sealed, dismissed, expunged or not you're required to report all this sort of thing on your application. Failure to do so is almost a sure guarantee to be rejected. Your best bet is to get the charges dismissed (or a finding of not guilty), but if your lawyer doesn't feel that such is likely, an ACD, while it will still need to be reported on the citizenship application and count against it will be better in the long run than a conviction.

I'd hate to hear the response that you want to have your drug charge dismissed because the impact of a criminal conviction would affect your attempt to become a citizen. But feel free to ask.