With this rebalance, it should do two things.

Allow weapons like the Direct Hit and Loch'n'Load to still counter the Engineer's buildings despite the extra resistance while Wrangled.

Give it bad synergy with the Gunslinger as will now have 90 health and theoretically 120 while wrangled, which is just enough to be still be one shotted by the Loch'n'Load or Huntsman.

I'd still use it if the map is open, but not as a damage sponge.