Hey guys, it's me. This is a homebrew rule I've been contemplating for use in my game, and I'm curious what you guys think of it.
In core, a 'high jump' is nothing but the deffinition of how high a given jump check takes you. It's no higher than a long-jump goes, just part of the same result.
My rule, in order to squeak a little more variety into this particular use of acrobatics is as follows.
High Jump: When making a jump check with the acrobatics skill, make the check as normal, and consult the table for distances. A high jump jumps 50% higher than the listed jump height, but only traverses 1/2 as far laterally.
It just makes sense to me, a high jump should be a jump that focuses it's energies into maximizing height, at the cost of potential distance covered. (And, if you notice, the cost to potential distance is more than the increased leap height.)
To get a baseline for this, lets look at the current High Jump world record: 8ft .46in. That's pretty high. The rules for acrobatics state that the DC for someone wanting to jump that height is 4*the vertical height. So, a DC of 32.
A 1st level character with 1 rank in acrobatics, 18 dexterity, the acrobatic feat and Skill Focus: Acrobatics and class skill will have a +13 to their check( assuming a barbarian, bard, monk, or rogue). Taking 10 gives them a total of 23. 20 divided by 4 is 5 ft. The same character taking 20(or just rolling a 20) can get up to 33, equal to the world record.
If we look at maximum skill progression and stat boosting going toward dex, then the maximum ranks and typical jumping height (taking 10) without gear look like this: 5th - 17(27, 6ft), 10th - 23(32, 8ft), 15th - 28(36, 9ft), 20th - 34(44, 11 ft). Natural 20's obviously combine for higher results. At 10th level these characters are taking world record jumps with ease.
Taking a normal character (non class skill as well), who maxes acrobatics, but doesn't bother with the feats will drop all those values down by 8. The highest level PC that could achieve a world record jump without aid of gear or class skill would be 8th level (20 + 8 + 5= 33) whereas a character setup to jump could do it at 1st. If we apply the +50% you're suggesting we end up with 1st level characters that can jump 12 ft high, and 20th level characters that can jump possibly 16 feet or more while naked.
Obviously I don't see any game breaking issues with this unless the events revolve around Olympic high jumping, but it stretches the bounds of human physical ability a bit out of proportion. From what I can tell, the rules seem to be built around the current peak of human ability (8ft) and seem appropriate, stretching that a bit isnt out of the question if you want it in your game.
I'm honestly curious why the vertical reach table was removed in PFRPG. By 3.5 rules, a human only needs to jump 2 feet to reach a 10' ledge, with a climb check covering the rest of the distance.