Provided you don't know what your opponent is going to build, an M36 is always the best choice.
Let's take your Ostwind/Sherman example. The Sherman does give more AI power, which is nice, but is vulnerable to any other OST vehicle from T3, or a panther, or most call-ins. Meanwhile, the M36 isn't vulnerable to those vehicles (when correctly micro'd).
As a result, the safest option is to preemptively build an M36, since this will invalidate any vehicle OST goes for, forcing them to either heavily invest in AT-focused tanks (STUGs, Pathers) or more heavily invest in AT-Infantry. For the former, the solution is simply more M36s, and for the later, your infantry should counter them.
The current Tiger HP gives OST a generalist solution to the problem, since it has enough HP to somewhat resist TDs, but also allows for the vehicle based AI that OST needs to survive late-game. Nerfing the Tiger's HP removes that, forcing the situation I described above.
I don't say this lightly, but the only solution to the current "60 TD Meta" is literally a rework of every tank in the game. We're currently stuck in a situation where either "60 TDs" are the obvious pick in every situation, or they're nerfed to the point where the game is unplayable. This needs to be fixed; and the only way to do this is by completely reworking how every vehicles relates to each other.
I don't agree with this. M36 is only the best choice if you are already winning the infantry game so you can harcounter the enemy armor when it comes out. However, if the game is even, or if you are behind, the M36 is not be best thing to go for as it will do nothing for you when it comes to winning the infantry game.