Hacking Japanese games into Chinese is generally much easier prospect than hacking them into English. Far, far, far less low-level work (interfaces, font width hacks, etc) need to be done. Given that proportionality is much more important in Roman tongues and that our character sets are based on sounds instead of syllables generally makes stuff like J->E a dramatically more complex problem than something like J->C. Neither is exactly a simple task, but it's sort of like the difference between quadratics and multivariate calculus.
I would agree with you normally about this for about 90% of anything from the PS1 era (with either Shift-JIS or Unicode) and beyond and the SNES era JRPGs which already have a few hundred joyo kanji.
But the Ganbare Goemon games use a 8x16 hiragana-only font (plus only the frequently used katakana, even the dakuten are stored in separate tiles) which has to load in its entirety in the VRAM and needs its compression figured out. I think for this one, the Chinese would have needed to do actually more
than the hacking required for a latin alphabet language hack.
That's pretty well known but that one didn't happen just because SCEA didn't think it was worth releasing.
(I've heard it's one of the worse Goemon games but a shame SCEA didn't let the market decide if it should've been released. )
Actually Konami did commission better 3D models for the US release.
It's a bit of a budget game that tries to be a platformer/Zelda OoT hybrid, and has tons of cut content, but is still pretty serviceable and certainly better than the first N64 game. Its main fault is the graphics.
SCEA vetoed lots of other niche games (that's why Chulip got delayed from 2004 to 2007 for example, among others).
If you're looking for the worse Goemon games, there's some of the PS1 ones and a particularly bad insanity-inducing GBA game.