If this happens, this could be the beginning of the end for DC Direct, at least for action figures.
Now that Mattel has the license for the entire DC Universe proper beyond just Batman and Superman with the DCUC line there is little to entice 6" scale figure collectors besides artist/storyline specific versions of the characters.
If HT (or any other 6th scale figure maker) gets the rights to their universe, their will be little point in continuing their DCD line of 13" collector figures since the scale is so close. If DC Direct's BB and TDK figures are any indication, collectors would be better off paying a little more for a licensed interpretation of the comics versions, rather than the ones that are "straight from the source".
Well, at least DCD would still have their statues.
DC Direct can easily continue with the Artist specific or title specific 61/2-7" figures. These have never been mass marketed there is plent of room for both Mattle's higher articulated figures and DC Directs more statue like figures.
As for the whole 1/6 line. Well if the rumors are true and Hot Toys has the master license to the DCU the question will become if they will see Noth American distribution through DC Direct or not. If not then the 13" Line can continue without problem and if they do distrubte them and price them in the 150-175 range like the TDK figures the 13" Line is going to be cheaper and people collecting that scale will continue. Again there is room for both but Hot tOys would be far superior.