Creating diversity in condition damage specs.
While what you say is true the whole system has been designed with the idea of same boons and conditions.
You would have to modify a ton of skills especially condition removals because removing 1 condition can now remove 25 bleed stacks stacked by 4 ppl while with 4 different effects you would just remove 1 making it rather weak.
Contrary to that removing more conditions (if they buffed number of those removed to cover for more unique conditions) would be especially powerful against single foes as it would remove in turn too many.