I've always thought it would be cool if DC were to purchase certain properties in order to create new series and a new team style comic. Most of these properties have been released at one time or another by DC, but I don't think they've ever actually purchased the rights to them. The first 3 come from the same time frame, which would make them perfect together.
First off is The Phantom.
For 21 generations, The Phantom has stood for the destruction of piracy, greed, cruelty, and injustice, in all their forms. The mantle of The Phantom is passed down from father to son, each one holding the name Kit Walker in order to protect the illusion of him being the same person back from the dead. The Phantom was the original comic book superhero, predating even Superman. The Phantom was the first masked hero portrayed as having no pupils in his eyes while wearing a mask, which is what inspired DC to do the same with Batman and eventually the majority of masked crime fighters.
The Ghost Who Walks, would fit in perfectly with the DC Universe. Never using his guns to kill only to wound and with there being multiple Phantoms throughout the centuries, there's no specific decade The Phantom would be stuck in freeing the writers so they wouldn't need to reboot the series every 20 years.
Second, I would bring in The Shadow.
Another crime fighter who predates Superman and even The Phantom, debuting on July 31, 1930 on a radio show. His origin has changed radically over the years, from being a French Aviator to a former war lord. The Shadow would fit like a glove in the DCU on a team with The Phantom.
Third, I'd rebuild The Rocketeer series.
Created in the 1980's as a pulp comic which takes place in the 1930's,The Rocketeer was brought into public fame by the Walt Disney Company in 1991.
Armed with only his rocket pack and a pistol, The Rocketeer battles the mob as well as Nazis.
Fourth, restore the Green Hornet to his one time fame.
The Green Hornet came along in 1936 from a radio show and eventually made his move into comic books and television as well as that horrendous film from 2011. At one time, GH even crossed over into the campy Adam West Batman series. Ignore the 2011 film, because Green Hornet's intelligence is meant to be equal to that of Batman's.
Fifth, return Space Ghost to his roots, no more of that Coast to Coast crap.
Created by Hanna-Barbera in the 1960's, Space Ghost has gone from superhero to campy talk show host. The majority of the readers on this site however, only know him from that God Awful talk show "Space Ghost Coast to Coast", but for those of us who actually remember his time as a Superhero, many of us would like to see him return. Though not fitting with the other characters of this editorial, as they're more Pulp and Space Ghost is more fantasy, he would offer a nice blend to the team.
Sixth, Blue Falcon.
Blue Falcon was created by Hanna-Barbera in the 1970's as a Batman-Esq superhero who took a back seat to his k9 side kick Dino Mutt. If DC were to purchase the rights, I could see BF moving into the lead role with Dino Mutt being less comic relief and more cybernetic police dog. By adding Blue Falcon and Dino Mutt to the team, DC could use them as a bridge between the Pulp heroes of the 1930's and Space Ghost.
Finally, I believe it's time to re-establish Zorro.
Pre-dating both The Phantom and The Shadow, Zorro was created in 1919. Another generation hero, Zorro also passes down his mantel from father to son. Originally, Zorro was used to punish cruel politicians in California before it's acceptance as a state. However, with the growing political domination of the US, DC has the perfect base to bring Zorro back into action.
As we know, the 80's brought us a team made of several of King Features characters such as Mandrake the Magician, The Phantom and Flash Gordon. Personally, if DC were to purchase the heroes in my list, they would almost have to include Flash Gordan and Mandrake as recurring characters and maybe eventually give them their own series. During the year of Super Friends: The Super Powers Show, we saw our DC Heroes joined by Hanna-Barbera created heroes such as Black Vulcan (which DC used as inspiration for their Black Lightning character), Apache Chief and others which many believe The Wonder Twins were also apart of, however they were actually created by DC specifically for Super Friends in order to take the place of Hanna Barbera characters Wendy Harris and Marvin White.