I actualy kinda enjoy that in Ox or a Bear shape im able to carry almost tripple amount of stuff back to vendor, especialy after some big fights ... since i dumped Strength ...
But i would totally agree that Cat (and possibly raven, didnt try that so far) need some adjustments. :-/
Again, I want to stress that this change could be made without reducing the benefits to these higher strength forms. As said above, Shapeshifting either melds your gear into your new form OR "is worn by it." Therefore, it would be reasonable to assume that when shapeshifting into a low Stre form, you would choose the meld option (so your new Stre would not change your carrying capacity), and when shifting into a high Stre form, you choose for your gear to be worn by it, and therefore your carry capacity is still increased in that form. The only question is whether Larian could effectively implement it that way.