So true, and while part 5 didn't have much slow down at all, there definitely isn't any in part 6 on AW hardware.
I think it was just a smart decision at the time for SNK to switch to newer hardware, as it showed they are not stuck in the past on their old hardware and are willing to move forward, along with somewhat newer technologies. If they didn't, we would probably have seen KOF XI, XII, and NeoWave on MVS, and honestly after seeing XII on Type-X2, would you want to go back? Part of me in a way would say yes, but in the technical prowess and achievement graphically that they did on XII, I say no.
It was probably a good decision, but it definitely left fans who had invested a lot of money in the Neo AES out in the cold (and the MVS system was always widely distributed in arcades, long after SNK dropped making games for it). So u had all these arcade owners with working MVS hardware but no new games coming out for it, after SSVS there was nothing. They could have at least tried to keep the Neo alive to some extent, for example 1 game a year or something. They could have released SSV Perfect in 2005(the year after SSVS), for example. SNK could also release hardware/software for Neo heads to create their own software, for example based on templates for Metal Slug, other shooters (easy to make games) etc. Instead they've apparently kept the hardware documentation secret, why would the technical documents for the Neo Geo still have to be kept secret after all this time, it's not like SNK are still selling games for the Neo. Even though the system is so old, it's still a mysterious system, probably not many people in the world know completely how it works, or how to get the most out of it. It probably hasn't even been pushed to it's absolute limit- for example the biggest game was KOF2003 at 716Mbit(89.5Mb), and they could go up to at least 1000Mbit without loading times, and possibly even higher if u were willing to accept loading times on games.
For all the technical superiority the Atomiswave and Taito Type X2 have over the Neo, they've still never really replaced the MVS/AES. Instead of it being a straight arcade to home setup like u had with the AES/MVS, now they're back to translating games to home systems (like Neo games to PS2, adding loading times, and KOFXII to PC/X-box 360/PS3- toning down the graphics in the process(?). Maybe SNK has lost track of the whole arcade-straight-to-home concept. That's what some SNK fans want, arcade-perfect games, no matter what the cost, even if that means u keep the graphics the same as the arcade, rather than improving them.
Sometimes when programmers are making games, it might even help to have limitations graphics-wise, as it forces them to make gameplay better and make the best use of the graphical capability they do have (with the Neo). Like for example in music production, sometimes experienced people decide to limit themselves in what equipment or techniques they are going to use, even though they have access to all the latest equipment, they might still use a synthesizer they have from the 1980's. That way it forces them to be on top of their game, and they are using equipment they are more familiar with than the newer stuff.
The Neo has so much potential still even though it's what 19 years old?
I thought it was 20 years old, they first started developing it in 1988/1989.
The AW didn't really add anything to make it better
Yeah, MS6 looks a little strange as it has low-res graphics on a high res background(Metal Slug doesn't need high-res, in fact the forground sprites are better if they're low-res). Also it doesn't need shadows in the backgrounds. They could have easily gone on forever with the Metal Slug series on the Neo Geo.