The title says it all, I couldn't find a post that was still active on this board that had any thing to the like. A lot of older players will remember this from back in Vanilla as it used to be in the tool tip for Intellect. But it was removed some time ago. However, it still applies even though Blizzard removed it from the tooltip.
However, a lot of newer players will spends hours leveling up weapon skills to 400 when if you buy a intellect set it will take <15 minutes.
Yes, I know this is old for people who know I'm just bringing this out again for people who don't know. Take it as you will.
Testing concluded for Proof:
All testing done with a Hunter with 0 Weapon Skill in Daggers and Unarmed, using an OH stat stick in both so I have no OH attacks. NO Other gear except + intellect was used during the Intellect test, NO GEAR other then the OH of Stamina used during the Non-Intellect test. Only other differences other then the intellect is the Weapon (which both have the same speed and starting weapon skill) and the Off-hand.
All times are the total time it took to reach the benchmarks. For example, with daggers to get to 300 weapon skill it took 6 minutes total. Not 6 minutes after I reached 150. In case there was any confusion.
Test 1 -
Dalaran Dagger (1.3 Speed, no haste, w/ Demon Skull Orb of Intellect): 501 Intellect, tested on Grol the Destroyer
Time to 150 Weapon Skill - 3 Minutes, 11 seconds.
Time to 300 Weapon Skill - 6 Minutes, 37 Seconds.
Time to 350 Weapon Skill - 8 Minutes, 12 Seconds.
Time to 400 Weapon Skill - 18 Minutes, 28 Seconds.
Dalaran Knuckle (1.3 Speed, no haste, w/ Demon Skull Orb of Stamina): 0 Intellect, tested on Grol the Destroyer
Time to 150 Weapon Skill - 3 Minutes, 18 seconds.
Time to 300 Weapon Skill - 6 minutes, 39 seconds.
Time to 350 Weapon Skill - 10 Minutes, 43 Seconds.
Time to 400 Weapon Skill - 59 Minutes, 06 seconds.
I only went to 300 at first, but then since I noticed they were so similar, but I was 99% positive that I saw faster gains, I went ahead and took it all the way to 400. As you can see the time it takes scales with the weapon skill (obviously, thats common knowledge) but the early levels are strikingly similar (only a couple of seconds off, and that could be due to the mob repositioning or what have you) without Intellect but the later levels there is an obvious increase in the duration it takes.
Hope this helps!