The maximum use of the ticket is more related to WHEN you book your award flight than where you fly. That's because a RR award ticket is equivalent to a refundable fare, usable for the "last seat" left on the plane.

But, of course, that doesn't make it a maximum value for you if you could have easily made your plans early enough to get a cheap fare. If you get several RR award tickets a year, it's practical to be on the lookout for "last minute" weekend getaways that would cost you up to $600ish cash. But if you've got just one ticket and have a "pent up" interest in travel, I'm not sure why you'd want to reserve the use of that ticket only on the off chance that you think of something at the last minute.

Meanwhile, as mentioned elsewhere in this thread, you can use it to fly to Dallas from cities where you can't book a direct Southwest flight to Dallas (you have to book two separate flights, one to a state adjoining Texas or to a city in Texas, then a separate flight from there to Dallas, and on these separate paid tickets they can't check your baggage through).

Putting those two facts together, a last-minute flight to Dallas from many states away might cost you over $1000 depending on the booking and still not get your baggage checked through, while one RR award ticket would get your baggage checked through and reduce the ticket cost to $0. It seems to me therefore that a last-minute flight to Dallas is clearly the best value from an RR ticket.

There are some other cases where Southwest can build iteneraries for you where published single-booking service may not exist. But they still have to be "the most direct" itenerary and with no overnight stopovers. These would most likely only help you if you're trying to fly to/from smaller Southwest airports (less likely to be needed by someone in Chicago, Los Angeles, Baltimore, etc). For example, from Amarillo to Boise there's only one daily published flight leaving 7:35 am. Let's say you want to fly from Amarillo to Boise but that's too early for you. You could presumably get Southwest to give you a one-way award booking which is a nonstop from Boise to Albuquerque in mid afternoon, then after a few hour wait at ABQ a one-stop direct flight from there to Boise in the evening. Southwest presumably doesn't make this published service because of the 4.5 hour layover at ABQ, but if that turns out to be the most direct route that gets you from Amarillo to Boise in the afternoon/evening, they would presumably let you book something like that as a single RR one-way award. (But again, this helps you more with the "when" than the "where" in terms of value.)