I'd mentioned this in the past (pre-7.3) and thought I'd bring it up again.
I think it would be great if there was more inclusion of the OPEN/CLOSED status of threads.
Example locations for this would be on the advanced search page, and in the Display Options for postlist (a check for "hide locked topics", etc.)
Should be easily accomplished by adding a ubbt_topics.TOPIC_STATUS = 'O' to the WHERE clauses in the queries (with board-specific appropriate prefix, of course.... just provided for examples sake.)
It would a great way to only search and view topics that can still be participated in while not getting topics that are locked/closed.