I think Type is the way it is specifically
because Wargaming needed a prize tank for various competitions. It's not competitively viable so that's not an issue, but it is one of the best moneymakers (though since the last round of nerfs, significantly worse at that and now regularly loses to Jagdtiger 8.8mm and is about on the same level as Löwe & T34 credit-wise, see
here) so it's a fairly ideal prize. It's also a good all-rounder so it offers something for almost everybody, which is quite convenient for a prize since anybody can win them and people don't really have control over what they win. Changing it to bring it back to sale would certainly be an option but then they'd need to come up with another prize tank from somewhere and that, I believe, would be more trouble than it's worth for them.
I think their approach is rather to introduce new, playable premium mediums for Tier 8. Still kinda waiting on that front, of course. T-34-3 is kind of a travesty (who even plays T-44-122 anyways) and FCM 50t lacks the camo to play the typical Med roles so while it certainly fits the "mobile paper tank with great firepower" archetype, there's another niche that would need filling. Honestly, I don't care either way, though Tier 10s in Type would be kinda annoying since you'd need gold to pen them when not flanking (which isn't always an option), which kinda defeats the purpose of a credit farmer. Yeah, I already shoot the occasional gold shell when the situation calls for it but with Tier Xs you'd have to shoot a whole lot or just accept that you're not going to be able to contribute in some games.
EDIT: Oh yeah, Type 59 G, well, let's just say it hasn't done too smoothly in China (what with teammates often killing any Type 59 Gs they see). I don't think the game needs such ridiculous multipliers anyways, nor extra copies of the same tank.