What keeps it from existing is a GM who doesn't allow for custom magic item creation rules.
The rules that you're using also include this statement:
Many factors must be considered when determining the price of new magic items. The easiest way to come up with a price is to compare the new item to an item that is already priced, using that price as a guide. Otherwise, use the guidelines summarized on Table: Estimating Magic Item Gold Piece Values.
The correct way to price an item is by comparing its abilities to similar items (see Magic Item Gold Piece Values), and only if there are no similar items should you use the pricing formulas to determine an approximate price for the item. If you discover a loophole that allows an item to have an ability for a much lower price than is given for a comparable item, the GM should require using the price of the item, as that is the standard cost for such an effect. Most of these loopholes stem from trying to get unlimited uses per day of a spell effect from the “command word” or “use-activated or continuous” lines of Table: Estimating Magic Item Gold Piece Values.
Since items exist that give skill bonuses, which is what you're getting here the real price should be done similar to those.
For a +10 to one skill, you're looking at a base price of 10,000 gp. Now multiply that for all the additional skills.
As a GM, that's the price that I would set.
Exactly, the basic just of that paragraph is "if it seems too good to be true" the GM shouldn't allow it.
The enhancement bonus vs competence bonus doesn't factor into the price IMO.
It's a skill bonus, and with it lasting 15 hours per day that's effectively all day. At best if I were the GM I might reduce the price to 75% for the time difference, but I'm going to make sure that situations arise where you don't get the bonuses when you need them.
You know, it's not really a drawback if it never comes up. Which is why I just said to price it the same as a regular skill granting item. I would allow you to change the type to enhancement bonus though, although that does enable some pretty crazy static bonuses to skills.
You could get +10 competence and +10 enhancement bonus to a skill for 20,000 gp.
Obviously I'm not accounting for making an item that does it for all int/wis skills, but just illustrating a point.
Agreed on above. It would certainly cost quite a bit more than 12,000gp. I just wouldn't quite price it as a static +10 to every skill, either.
Drawbacks need to come up to count, but bonuses need to come up to count, too.
Was there something you had in mind you wanted this item for, specifically, or was this more an exercise in custom magic item shenanigans?
A 15th level wand of Tears to Wine would run 11,250gp retail and require no custom item rules.
Yes, but each charge would only last 150 minutes. VotM spell lasts 24 hours, closer to the 15 the OP was asking for. IDK, maybe your solution is more what the OP wants.
VotM works only on the spellcaster, while a lot of creatures can drink from Tears to Wine: At caster level 16 you're looking at 300 bottles of wine.
Ultimately what this boils down to is that pricing magic items is not a science, and the rules that are there are just a very basic guide. They are not rigorous, and applying them without looking at what else is available could lead you down some very wrong paths.
I think many of us remember the whole "Ring of Constant True Strike" thread.
Heck, even at level 3 when a Druid first gets this spell ...
Does that mean that 37 creatures, or possibly MORE, can get a +2 on skill checks for 2 different stats, for half an hour, out of a SECOND level spell? That seems... kinda bonkers.
Yes, that's completely bonkers.
Because Tears to Wine (d20PFSRD) is a 1st-level druid spell, not a 2nd-level spell, and is available right at character creation, not level 3.
For a +10 to one skill, you're looking at a base price of 10,000 gp. Now multiply that for all the additional skills.How would you price an effect that covers all int or wis skills? Especially craft and profession skills as they are skills with multiple fields?
You estimate. As I said previously, it's more art than science when coming up with magic item pricing.
I would very likely just account for 1 craft and 1 profession in the cost, along with all the other int and wis based skills. And for each one add another 10,000 gp to the price. And see where that landed on the price. Maybe I make an adjustment (up or down) to the price for having so many effects crammed on one item. Really as a GM you just have to toy with the pricing until you feel comfortable with what it does for the price.
The main thing I wanted to point out is since we have basic rules for skill bonus items (for a single skill) that price out as bonus squared * 100 gp (and plenty of examples of that in magic items) that should be our first point of reference. The next thing to look at would be magic items that provide bonuses to multiple skills and try to analyze how they are priced.
Ultimately is going to be up to your GM to decide what is acceptable.
As a GM, I certainly wouldn't allow an item that gave +10 to all int and wisdom skills for only 50,000 gp.
Rather than looking at an amulet of mighty fists you should really be looking at magic items that grant bonuses to multiple skills.