Not sure about FPGA based system tbh - I hope they never do an FPGA based system! Basically I think the problem with those systems (eg. SNES Mini, Retron etc) is they just aren't original hardware, and then I would question why just not emulate instead? I know you can get a higher level of perfection in FPGA vs emulation, but it just feels artificial to me and pointless when emulation is there for free.
From what I've gathered, the primary arguments for FPGAs over emulation are lag and preservation of the original hardware. While modern emulators have made strides in lowering lag, platformers (which the NG has a paltry few) and fighters (which the NG has oodles of) remain particularly suspect to it. Combined with the display lag added by modern displays, the end result can prove quite distracting. As for the preservation aspect, the original hardware has a finite lifespan, and at some point in the (distant) future, FPGAs will be the closest thing we'll have to it, save for museum pieces and a handful of units owned by well-off collectors who can afford to keep them running.
I guess the other thing to consider is cost vs demand. There's a fine line there somewhere I guess, because I am happy for FPGAs to be used to improve video, add SD functionallity, additional features etc but I just cannot ever see myself buying an FPGA system that replicates entirely a particular console.
I think the choice boils down to personal preference: Collectors such as yourself will continue to prefer original hardware, while newer initiates to the scene might prefer FPGA-based products. I own several HDMI-modded systems and flashcarts, so I'm all for using FPGA-based products to add new functionality and features, too. I just think a full-blown FPGA implementation is the next logical step, especially for folks who aren't already heavily invested in the platform. As you pointed out, some people might still prefer emulation since it's essentially free, but I think the people on this forum don't belong to that crowd.
I also believe the NeoSD has proven that even within a very niche market there is a demand for FPGA-based products, and that they can be profitably made. (I assume the NeoSD hasn't taken the team to the poorhouse, since they're still coming up with new products.)
That's one reason there are so many of those types of devices, everyone keeps producing more and more of them and it just feels like from an original hardware collectors perspective just more tat on the market. I am not looking forward to the new Atari system for that exact same reason... I guess if the Neo Geo X had been done properly with FPGA hardware, and had it had correct aspect ratio, then maybe that would be desireable because its portable and branded SNK, but that turned out to be more emulation tat.
You hit the nail bang on the head! "Just more tat" is definitely not what I'm after, and the NGX debacle is the perfect example of how not to go about creating a "reimagined" console. So whoever's going to be making a FPGA implementation, will, in addition to technical acumen, need to have tremendous respect for the platform, which I think the NeoSD team, like
Kevtris (trigger warning: mentions the Analogue NT Mini), has in spades; this is why I suggested them in the first place.