But...but all tanks ultimately need to support friendly infantry and destroy enemy infantry. That's the entire point of them. Don't confuse this with being solely an infantry support tank, like the interwar heavy tanks, that's not the same thing at all. But the bulk of all WWII tank combat was against and in support of infantry, pure tank on tank battles were relatively rare..
Not ultimately. They need to fight off inf aswell, but in germany its main task was to fight tanks.
Think about a Sherman "meeting" a Panther, after that you have a Panther that can support its INF, but the Sherman can't, because it was shot down.. Where is the purpose of a tank that can't fullfill its main role -as you put it- of Inf support when it is shot down? That flaw in US approach become more clear after the landing in Europe and was brougt up several times to high command. There was struggle up there to field some tank like the Pershing much earlier to get rid of the initial TD/Inf-Support-Doctrine.
Shermans were designed to be Inf-Support tanks, wich are not to mistaken with the UK-Inf-support tank designs.
UK had their fast cruiser exploit,slow inf support tanks doctrine, while US had Inf-support and TD doctrine. Exploitation should be done by these Inf-Tanks and TD support called in when enemy armor sighted.
Germany had the main combat vehicle that had to fight off enemey tanks at first, to eliminate that threat on the battlefield. That was already with the PzIII that way. Some PzIV with short gun should aid Inf in fighting down strong points.
Similar for SOV. Thats a complete different approach that was later incorpotated by western allies after several years of hard lessons learned and finally convincing high command that their old approach was not that good at all.
Bad steel wasn't an issue with the panther's final drive either, although that would still not be an excuse even if it was, even reproductions with modern steel have been shown to fail. You simply can't power a 45 ton tank with straight tooth gears..
The bad steel was named in the first link to gave a bad armor protection.
And I agreed already that the final drive was a point to improve. It was used very likely that way because of cost savings or more advanced gears were used already in Tigers.
They could have used a more advanced version like used in Tiger though if they had the luxury to still do so.
Why didn't the french did that? Maybe because they just used salvaged/captured vehicles and it would have needed some modificatiosn to the chassis? Or they lacked the industry to do so in the early afterwar years?
Why are you now assuming I think all German designs are crappy? Some were, some were not, some were excellent, I'm only talking about the Panther here though, and I've not even brought up half its problems - just the main ones. The Panther made its debut at Kursk and for its entire service life Germany was on the strategic defensive. You can't say "Hey the Germans won some battles so the Panther must be good", one does not follow from the other, but regardless the Germans weren't winning any great offensives with the Panther. They made their great advances while using better designed and more versatile PzIIIs and IVs and 38(t)s as well as the fairly laughable Is and IIs..
Sorry, it was ment as an exaggeration. As if the Panther would have been a soo bad design, they would have switched back to PzIV or whatever. After all Panther was next to PzIV the main combat vehicle.
So you are saying that if you win offensives with a tank design then it is a good one? And if you are only at defensive it is not?
I sure don't get the link between being able to do offensives and using the Panther on a strategical scale.
You named already the PzI/PzII -wich were training tanks by design used in combat roles- and "succeeded" too on the offense.
As an aside, you might want to not disparage victories where the victor has numerical supremacy when defending Germany's performance: Virtually all Germany's great victories happened while they outnumbered their opponents. Even during the great advances of Barbarossa Germany and allies outnumbered the forces the USSR has on their front.
Disparage, what, seriously? Germans outnumbered their enemies all the time then? I'm not sure where you get your numbers or your logic..
Sure it is said they gathered some more men on the initial blow in the east, and the soviets were not fully prepared and their forward defending idea left them without cards fro the rear ares etc..
But at the same time soviets had still 3-4 times more tanks, 3 times more guns, and 3 times more planes too at hand.. ups..
Same for France, it is said Axis had more men, but surprisingly allies had more tanks, guns and planes..
So aren't that interesting numbers too. Just looking at soldiers alone and not at the amount of equipment the "few" russians had at hand. And sure they used outdated tanks, and the germans had only top notch equipment..
And have you thought once about the speed the germans were advancing?
Can you think about how much of your units that mostly rely on soldiers marching and horse trains can keep up with the enemy or even their own mobile units. Even the mobile Divsions had hard time to catch up with their spearheads.
So many fights were not done between german numerical superiority just because these numbers where marching behind and try to keep up with the mobile forces.
Not all battles were fought with the preparation like at Kursk/Charkov etc..
Germans were not winning by numbers most of the times but because of using better tactics and command chain. That is still overseen by much people even nowadays.. The strict CoC of soviets or western allies lead often to a tactical disadvantage that germans often used/expolited.
Just for your information. Later NATO used retired German Generals to hep them find/test tactics/strategies to fight off numerical supremacy estimated soviet forces in a possible coming war.
Why did the asked for their advice? Maybe because the germans allway had the upper hand in numbers at their victories?
Or just maybe they were quite good to fight off up to 10 times in numbers in ww2? Even when they used bad designed equipment?
So in the end, If you want to still think that Panther was a "bad" design thats up to you.
I think it was a quite good design. I also think that about the Sherman or T-34 regardless of the problems that also these tanks had.
Be it the role given or the enemies they had to fight or the quality of their productione etc.
Thank you for sharing your views.
To get this back to OP: 
Deciding if we want to build more cheaper less capable AT vehicles or top notch equipment wich is costly is a good game element imo.
Usually I would make the decision what to build depended on the game situation. Normally I would use my better tanks in locations where the enemy has equal forces and the weaker ones against other forces. So I wold choose a middle ground and have some few very good and a main tank wich could be some weaker. -> Build some Tigers/Pershings and much moar PzIV/Shermans.
Thats opposite to the initial german doctrine where some main tanks had some anti inf tanks as support. So some normal good overall and some especially good at AT.
From what we saw in history though, on the grand scale it is maybe best to have one main tank that fills all roles at all times. It doesn't have to be the best in all areas, but must be good enough in all.
If that is possible in game terms it would maybe an 75mm long gun PzIV right in 1936.. And the Sherman gets an extra research for a long 76mm gun too.
(ISR managed to even field a 105mm gun in Cold War in upgunned Super Shermans!)
For gameplay reasons to have good/bad equipment.
I tink it would be fun to have some "prototyping" of some sort, or "rush into production"?
So you could research a tank design and then need to invest some more time(money?) to iron out some of its designs. Or can send it just like that into production/combat and have a slightly worse tank at first that gets better later on(timed modifier wich adds more attrition)?
You could make it even so that some points would randomly never get better again. So you could get a tank wich is overall better but not in speed or protection much better as the older design?
So that way you can modell the Panther as a tank that has higher attrition(maintenance), but overall higher stats, while a Sherman would have lower attrition, but also worse stats.
Well having in mind here anti tank(HA) values, anti inf(SA) could be depended on available munition or type of gun design(anti-tank/anti-inf) and ammo research?