You're right on the money as far as locations and price to value.
The thing about Grove Park is it's proximity to Midtown, the development of Westside Reservoir Park, Bellwood Quarry, Northside Drive, GT, Howell Mill Rd, the quiet kept but thriving Riverside communities and Moore's Mill Road.
I love this area is terms of potential and proximity. One of the issues I have with the area is the topography and landscape. It kind of makes the area unattractive. A lot of open fields with withered trees and what looks like fields of thorns and shreds on tree bark. This isn't in all of the areas, but once you head above Donald Lee Hollowell you'll notice it. Trees in Atlanta are usually what attract people, but the ones here can keep the light out most times and as a result it looks dark outside about an hour or so before it should. I'd give this area a A in terms of development potential to price ratio, but only a C or so for attractiveness
East Point and Hapeville are hidden gems. Close to the airport, all major highways, less than a 15-20minute scenic route ride from the cities, and another 15min or so drive outside of rush hours. A great sense of community in both cities. Hapeville has higher cost housing/better architecture and more amenities, while East Point offers a greater sense of City, proximity to Atlanta and greater appreciation based on CoA developments. The Aerotropolis Atlanta development which encompasses both cities also makes the rumblings that much louder.
If we're talking about developing areas ITP, all three of these areas would be Top 5 or so on my list (in terms of areas seeing great amounts development and appreciation, rather than areas who have already seen both and are only experiencing marginal changes now). I'd say these areas rank at a B+/A- in terms of potential and and B+ in terms of attractiveness
