Or at least decent text editor, which allows to have one physical line per paragraph in plain-text messages but wrap these long lines visually to size of the ed

Or at least decent text editor, which allows to have one physical line per paragraph in plain-text messages but wrap these long lines visually to size of the editor window. As simple as that. Or good quoting engine. Does somebody remember FIDO's editor GoldEd? It made perfect multi-level quotes int most complex situations without problem, re-wrap and re-format lines to fit it in 80 columns (without breaking quotes in process!), it was real pleasure to read long threads because you always know who wrote what. And if you see broken quotes in echoarea you know, it is from usenet user, received via gateway with their shitty news clients. Thunderbird is still shitty in this regard, 30 years later.