I doubt the 3DS could run Dragon Quest 8, I think you'll have more chances with a Vita version.
My impression is that the 3DS is slightly less powerful than the Wii, which was more powerful than the PS2.
On the other hand, I just watched the trailer for DQ7 3DS again, and frankly it doesn't touch DQ8 PS2 graphically. The 3DS port of Tales of the Abyss (originally on PS2) also suffers from some framerate problems and has inferior graphics to the PS2 version. I have no idea if it was a quick-and-dirty port, or if they were pushing the limits of the system, although I would put my money on the former.
Which means next to none. Frankly if a port to a decent handheld was made, it might not even be localized. Dragon Quest 7 (for 3DS) is ready for prime-time but Square hasn't even made a peep about it coming to the west, or even the recently released (and decline) Dragon Quest X.
Porting Dragon Quest VIII to the 3DS or Vita wouldn't need any additional localization work. They just released it on iOS and Android. Any necessary localizations are done, other than a handful of references to the specific hardware it is running on.
Unfortunately, the current stance on releasing Dragon Quest VII 3DS is:
“Going back to people who want DQVII to come out… we’ve gotten a lot of requests, we really want to do it, but right now, we need to hammer out what kind of resources we’d need to do it. We say this a lot, but, we can’t seem to get to the point where it’s justifiable.”
Source:
http://www.siliconera.com/2014/08/3...est-vii-3ds-west-arent-sure-itll-sell-enough/
It seems like they are basing this decision on the sales figures for the DS remakes of IV, V, and VI, rather than the figures for VIII and IX. I don't know if that is the best comparison. VII is a somewhat more sophisticated game than those that originated on the NES and SNES. Those DS remakes are based on the PS1 remakes, and they look like blocky PS1 games. The 3DS remake of VII looks much more like VIII and IX.
Dragon Quest has never been a mega-hit outside of Japan. They've been crowing about how Bravely Default has sold over 600k copies outside of Japan, which is still less than half of what either DQ8 or DQ9 sold outside of Japan.
What they should do is get the localization finished in time to launch it in a cross-promotion with Bravely Second. This could mean selling both games together at a discount, adding a special gameplay item or perk if you have both games, whatever. If Bravely Default really has sent them the message that people still want to play classic JRPGs, then why not strike while the iron is hot?
Damn, now I'm itching to dig out my PS2 and hook it up just so I can play Dragon Quest VIII. I got about 25 hours into it when it first came out, but not long after that I got a job at EA, then on to Rockstar, and then had two children... At this point, I think I'd need to start over.