Redmine is great. Serves us without issues since 2007. I honestly don't understand companies using products like Jira when Redmine is available.
Does it still require filling an update form to change any aspect of a ticket? Maybe we've used an outdated version or it was poorly configured, but I remember switching to modern Jira at other company to be a huge UX improvement, with interactive and responsive everything.
Yes, I guess it still does, and for me it's a great thing, as you can do multiple changes at once and the recipient will just receive a single email notification.
By the way, considering Jira's slowness and sluggishness, I think it even takes less time to submit the entire form in Redmine.