I heard back from Regent on the missing dress codes on the new web. The basic message was as follows.

"The dress code was on the web site before the update from the days of Casual, Informal and Formal nights when specific dress codes were in place. As the dress code is now Elegant Casual every night with the only variance cruises of 16 nights or more having Formal Optional nights it seemed unnecessary to consistently list Elegant Casual"

In reality this is true. The best meals for the restaurants are the Captains Welcome Aboard and the Captains Farwell. Almost always the second night out and the second to last night on the ship. Only variance would be if one of those two nights it was a very late departure from a port a rare occurrence. So if you are on a cruise that is 16 nights or more then these two nights will be the Formal Optional nights.

If you do not make alternative restaurant reservations on those two nights you should nearly always be just fine. The Society Night seems to "float" around and is often on my contract as XX night then the ship changes it for situations that develop on board. So I am sure they dont want to post that as it will be constantly changing anyway.