Pack Rathound should prevent you from getting completely encumbered

[Barry]

It has very little reason to be picked up because not only can the player simply manage their inventory better but there already are several ways of increasing carrying weight capacity and 50 is insignificant for high-strength builds. If it were to prevent you from getting completely encumbered (capping it instead at heavily encumbered) it would be extremely useful for the actual hoarders this feat panders to that want to take everything not nailed down because they don't have to make several return trips.

[Barry]

Also, I don't think anyone in the history of the game has ever fully specialized Pack Rathound to 10 points, it should be 5 points for +10 carrying weight at the very least

[PaposikG6]

Pack Rathound can be useful for low STR builds on characters that require carrying around lot of stuff and do not need too many feats too work. For high STR it is obviously rather useless. You can of course use Lifting Belt, Infused Pig Leather Boots and eat Pentapus Barbecue, but those things take up a slot for respective belt/boots and food, making you less effective in combat.
But yeah, Pack Rathound Specialization is quite bad.