I honestly think it would be cool if he developed a bond with Catwoman like she became a mother figure to him and as a result he became Red X from Teen Titans. I think this would be interesting because Talia is a terrible mother after everything she's done and Selina given her relationship with Bruce is the closest thing to a step mom Damian really has given her relationship with Bruce. I also think it would be interesting to see Selina in that kind of relationship where she's responsible for someone else's well being.
One way I can see this happening is that maybe she and him could end up in a bind and forced to work together mean while the majority of the Bat Family is out of Gotham ultimately causing them to watch each other's backs. Another reason I like this is it would create an interesting dynamic with her and Bruce it would also really add to the rivalry between Talia and Selina.
The reason I'd like to see Damian become Red X after becoming close to Selina is Red X is like a hybrid of Batman and Catwoman he's like Batman in his grim appearance but he's definitely got a flirty and funny personality of Catwoman and I think it would be fun if after being made to team up with Selina and bonding with her she started rubbing off on Damian. Besides I'd love to see Bruce react to Damian becoming a thief.