You can see the high level fireworks from some of the standard view and BW view villas and at a distance from some of the RIV standard view villas on high floors. There isn’t any place outside of Epcot itself that allows a view of the lower level fireworks or the parts of the show that occur on the lagoon.
Boardwalk view rooms at Boardwalk, especially higher floors and the ones down at the Swan/Dolphin end of the Boardwalk, have very nice views of most of the fireworks and some lasers - but you won't see the bay-based water and projections. You can also walk from any of the Epcot-resort-area resorts up to the International Gateway, and see much of the show right before the turnstyles without actually entering the park - if you don't have park tickets that day...if you do have park tickets, the International Gateway drops you right onto the World Showcase Lagoon to see the whole show and then exit quickly without dealing with the mass crowds headed to Epcot's main entrance.
I’ve enjoyed the Epcot fireworks from some of our BCV stays. They aren’t spectacular to be sure, but I’m still in heaven anytime we don’t feel like walking into the park the night before a runDisney half or full marathon.
Also, a tiny side note…the new Epcot show, Luminous, was a tad disappointing, and MK 100% is now my favorite at WDW. We really enjoyed watching it from our BLT theme park view. (I really actually miss Harmonious, barges and all. )