I know that for some reason the Recalbox maintainers don't see Atari5200 und Atari800/XL/XE on the radar. But given the recent enhancements by the Atari800 emulator coder Tschak909 it would be really really nice if someone would integrate his work into Recalbox.
I'm not sure how much of work is required to integrate the libretro stuff from Lakka to Recalbox but technically I think it would be straight forward, because Recalbox is libretro-based too.
From the retro value point-of-view the Atari 8bit line is for sure an important "influencer" platform. Many legendary 8bit retro-games had their roots Atari's 8bit platform. Games like Boulderdash, MULE, Dropzone, Ballblazer, Alley Cat, International Karate and Bruce Lee all appeared first on the Atari.