I like the OP idea as well but it's more akin to "Rebel insurgency" like the TEC has.
Using the DE for fleet support is definitely a plus but there are a lot of variables--coordinating the hit, keeping your fleet in use or alive while waiting to arrive in sync with the shot. telegraphing your fleet target intent as soon as the shot is fired, the logistics and military burden of the research to get the DE.
A Kostura--when properly used, gets your WHOLE fleet to the target and impacts it immediately. The Novalith can take worlds out. alone. The DE requires a lot of investment, research and attention to work and doesn't work half as well.
I made a post suggesting the DE capture culture centers in the gravity well where it hits. GoaFan suggested maybe just destroy them. Volt_Cruerlz already made a mod for Rebellion of it and you can try it out.
If you have the modding skills, you can pretty easilychange it to capture ships or just destroy the centers.
Will make a good testbed for ideas here. The link is here.
I tried using that idea Yurka in my own mod but I couldn't get the "EXPLORE" bool to work on a weapon it seems. My idea was there was to take Reverie and make them explore until they took enough damage. Bummer. I think it's one of those abilities with hard code stuff.