Makes no sense. Better WT should be better. There should not be a downside to having a higher WT.
How is this different from a 20th level barbarian taking longer to heal than a 1st level thief in d20?
At 1 hp/level/day the thief would take 5 days to recover from 5 damage, the barbarian would take 1/4 of a day. The barbarian heals 20 times faster than the thief, not slower.
Although more exactly a 5 point wound to a 1st level character is a major wound while it is little more than a scratch to a high level character due to how the system works. The 1 hp/level/day accounts for this. 1 point of damage on the level 1 thief is equivalent to 20 on the level 20 character. A level 20 character is 20 times better at not suffering or suffering from attacks. It works well for combat, but it does fall down with the overly simplistic dX/10 feet falling rules which should account for level with level * dx/10 feet.