I'd rather have consistency than accuracy myself, but this is more a question of Asian languages not being spoken like they're written, which ain't exactly rare.
Uh, Chinese, and... what, exactly? To my knowledge Korean is phonetic, while Japanese uses Kanji it does have a syllable based system, and ... well, honestly I'm not sure about Vietnamese, Cambodian, etc. But even Chinese has a phonetic system (pinyin). And one thing's for sure--Anglicizing the pronunciations (well... hell, any part of the language) any of these languages is fitting a square peg into a round hole, which I now realize was your point.
Anyway, time for some mental masturbation because it's the DL. Translation itself is a creative process (direct translation doesn't actually exist since the translator is acting as a filter), and if the translator's goal is to keep the pronunciation of name in tact and get Americans to pronounce it correctly, then varying translations is going to happen. Square peg, round hole, etc. However, another course of action is to not bother keeping the original names. Here, I'm with you 100%--consistency should take absolute precedence. Tina isn't Terra, and Terra is always Terra. The PW games get this head on by completely renaming everyone. But then you get people bitching about "OMG WHY DIDN'T THEY KEEP THE ORIGINAL NAME" so you can't please everyone on that one.
Of course, there's option 3--Fudge the phonetics and spell it like you'd spell the characters in romanji/pinyin. I don't think it works so well with voice acted games*, but it is fine if you really don't care about the audience pronouncing names correctly in their heads. Now, if you're going to argue that for the sake of consistency, different localization teams shouldn't pick different objectives with their names? That's a fine debate in and of itself, and I'm not sure where I stand on it. It's worth noting that it's not what happened here, anyway--Tseng should be Tsong in that case.
...Wait. This little interlude started because someone was bewildered by a more modern translation DEVIATING FROM FF7'S.
wat
I appreciate the opportunity to get all translation/linguistics-wanky, but... wat.
*Funny story. Before learning Chinese a little bit, I was really, really confused as to why they pronounced Zhuzhen "Jew-gin" in SH1's ending. And now I know.
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Oh, yeah. I play video games I guess. Um... 16 more scrap metals to my TF2 scout hat? Yeah. Relevance.