If you read this before editing, ignore it... Thanks for the add-on. The different restrictions/benefits are fun.

Trying an Oboroguruma character now. I'm mentally picturing a self-propelled carriage with half a dozen steamsaws mounted on the sides. >;) I've got a few ideas for small improvements to the Packed Car informational effect:

• It would be useful for the effect to have a "countdown" display, like on Step Up or Lightning Speed, to show how close you are to being "full".
• Game-icons.net is a great source of icon images for effects like this. I'm partial to the Old wagon
  icon myself. ;)
• You should probably superload Actor:levelup() to call :hinnagamiUpdateSlots(), as you're already doing with Actor:onWear() and Actor:onTakeoff(), so that the effect display will reflect the player's newly increased load capacity.
• Might be a bit "overkill", but you could also use the Object:descMisc hook to add a note to the object descriptions of suitable equipment about how much space it takes to wield.

Seems the mod is incompatible with the Wilder Balance mod https://te4.org/games/addons/tome/wilder-balance that adds a psiblade side to the class. Using Psiblades as a Takonyudo doesn't let psiblades appear, keeping talents that depend on them disabled. Bug doesn't seem to appear on vanilla races with Wilder Balance enabled, tested with Human.

Found another problem, in your superloaded Actor:canWearObject():

local base_canWearObject = _M.canWearObject
function _M:canWearObject(o, try_slot)
        local ret = base_canWearObject(self, o, try_slot)
        [...]
        return ret

The problem is that the base Actor:canWearObject() returns multiple values, and you're only passing through one of them; the value you're dropping is the message explaining why the player can't wear the object, so we end up with messages like "player can not wear: Special Thing (nil)." instead of "player can not wear: Special Thing (not enough stat)." What you need to be doing here is something like:

  
local base_canWearObject = _M.canWearObject
function _M:canWearObject(o, try_slot)
        local ret = { base_canWearObject(self, o, try_slot) }
        [...]
        return unpack(ret)

to pass through all the returned values from the base method.

Lots of interesting races in this addon [you should probably update the addon description to mention them... ;) ]. Small bug to report: the Mekurabe talent calls Actor:combatSteampower() without checking whether the method is actually present, which causes the game to go into an infinite error loop if the Embers of Rage DLC isn't active for the character.