For me, adition of ATARI 800 to Recalbox is more important than dreamcast or psp, ps2 etc ...
i think the "retro-value" of ATARI 800 is huge!! ; the retro-value of dreamcast is "ok" .
Since "ps2 era", games are easyly availabe in other actual platforms and, in other hand, i think RPi 3 is not enought for run correctly ps2, dreamcast or any console since "ps2 era" ...maybe i am wrong ???
If with RPi 3 runs "until" N64 and ps one correctly (and, it does! specially ps one) , is fine for me :)
Maybe with futures Raspberrys or similar microcomputers you can run ps3, ps4, ps5 jaja.... its only a time thing
"Saludos" from Chile ;)