You raise a valid concern, especially given the close proximity between DHS and Epcot. I can imagine the non-enthusiast guest comments now: "Honey, we waited three hours for this stupid Star Wars laser ride, but it was the same as that mousetrap ride we rode in Epcot this morning!"
However, if the rumors are true that the battle attraction will have guests exiting the vehicle then re-boarding, it might make for a different enough experience that the average guest won't notice or mind. On top of that, I could see the hype of Star Wars and the existence of the Millenium Falcon attraction watering down most of the negativity around duplicated ride systems.
I'll admit I'm biased here, though. I'm sure I'm not alone in wanting our own copy of DL's Indy ride somewhere on property, even though it's ride system and track layout (and smell) would be an exact clone of Dinosaur.