if these games r running on systems with the appropriate RAM requirements and experiencing the same problems as the handheld systems,then its not a RAM issue,but most likely an Emulator programming issue.if you're going to make an emulator, you'd want the most popular games or most well known to run first. that's probably why odyssey works with the switch emulator, all the way to completion. I don't know how many fps that is though. there's no way in hell my laptop could run the thing at a decent speed. I was getting about 15fps with dq 11 on the pc. the opening ran fine, but the game itself was slow to the point of unplayable.
the Vita has proven 2 exceed the PS2 in terms of graphics on games like KZM,BL2,AC3,etc. so its probably not a question of IF it is possible,but rather if the community can provide sufficient motivation ( $$ ) 2 the hacker/programmer(s) most suited 4 the job of developing a suitable Emulator. because i imagine after the success of Henkaku,TheFloW and co. r probably bizzy with more profitable ventures.