Level based weapon damage meant to assure that even if leveling players wont swap / equip appropriate to their level weapons, they will still be viable and handle the content, even if albeit with more effort.
It's clearly meant to bring a better and smoother experience for new players and probably to prevent them from leaving the game too early over inadequate gear choices.
The main issue is that at high levels this addition only makes testing and weapon comparison cumbersome.

Level Base values:

• TR: 86.65489
• CW: 144.42482
• DC: 144.42482
• GF: 173.309784
• GWF: 173.309784
• HR Melee: 86.65489
• HR Ranged: 144.42482
• OP: 173.309784
• SW: 144.42482

Weapon base damage comes from the slotted weapons. In game for damage calculations it will be number between the weapon min and max. To compare weapons the most simple way is to use their average.
This thought, has two exceptions:

1. TR - Both main hand and off hand adding to the damage. The 'combined' weapon is the sum of both weapons.
2. HR - Uses the Bow weapon damage for all ranged stance calculations and the blades for all melee. So those should be compared separately.

With a given base power, we can compare dps increase to increase in power:
At base\Current Power of