Including descriptions of the average, minimum and maximum heights of the ethnicities (which are indeed given in the Inner Sea World Guide and Inner Sea Races) is most definitely not 'vague descriptions' regarding their heights. The weight differences can easily be considered vague descriptions, so a Golarion human ethnicity height table need not include the weight aspect. Please provide some clarification to the questions below (which are from the definitely not vague descriptions of Golarion human ethnicities). By doing so you will be providing GMs and players who prefer to have a random height table that better results in averages that make sense for the definitely (not vague) height parameters that have been officially published.
Vague descriptions is not accurate regarding the average height descriptions that are given in the ethnicity physical write-ups.
As determined from the random height and weight table from the core rulebook: The average human male is 5'9" and 175 pounds. The average human female is 5'4" and 140 pounds.
Garundi:
ISWG: "Typical Garundi are rather tall and solidly built."
ISR: "The average height for Garundi is several inches taller than the average human overall"
The above two officially given descriptions tells us that the average Garundi is definitely taller than the 'average' human (as determined by the core rulebook). Can you at least clarify how many inches are meant by the ISR description of 'several inches taller' - or the range that you consider several? What is the minimum height that you consider 'rather tall'?
Mwangi-Bekyar:
ISWG: "The Bekyar are exceedingly tall - many topping 7 feeting tall"
ISR: "Most of the isolationist Bekyars stand a head taller than other Mwangi and have muscular builds."
By the phrase 'topping' do you mean that 7 feet is the maximum height or that is the minimum height of the many that top 7 feet? If you mean that 7 feet is the maximum height then what is the minimum height that you consider is 'exceedingly tall'? 7 feet tall is not a viable height generated by the table in the Core rulebook. Bekyar as a whole are 'exceedingly tall' - meaning the standard human height range table would be greatly in accurate to use to generate a random height for them. That is the purpose the random height table - for GMs and players (who choose to do so) to be able to roll randomly to determine the height of a PC/NPC.
Mwangi-Mauxi:
ISWG: "These tall, patrician folk"
We now have three different ranges of tall from only Garundi, Bekyar and Mauxi. What is the different height ranges for "tall", "rather tall" and "exceedingly tall". They are obvious different (hence we know compared to average humans we know the average heights in ascending order are standard (core rulebook) human, Mauxi, Garundi, Bekyar.
Mwangi-Zenj:
ISWG: "The Zenj are slightly shorter than average humans, with slender, muscular builds with wiry black hair."
ISR: "The Zeng people of the continental interior and southern savannas are both the most numerous and the most varied in their coiffure and attire; they're the shortest of the Mwangi people and tend toward compact, athletic builds."
So we know from the descriptions for the Mwangi ethnicities that the height average for each is different: in ascending order: Zenj, Bonuwat (which would be standard core rulebook human average), Mauxi, Bekyar.
Shoanti:
ISR: "Shoanti are powerfully built, and often stand more than 6 feet tall as adults."
This one is easy enough to figure out as 6' is not more than 6' and often can easily be viewed as not quite the majority. The word often used as a parameter also tells us 40 to 50% (as that is the definition of often in the 3.5 D&D Monster Manual - as Pathfinder used the 3.5 rules set as the base rules set).
Tians:
Not touching on the weight/build differences, there are only two relevant officially given descriptions regarding Tian heights.
ISWG: "Tians tend to be smaller and slighter than people of Avistan and Garund. Men only infrequently grow as tall as 5 1/2 feet, while women often barely break 5 feet in height."
Dragon Empires Gazetteer: "As with their neighbors, the Tian-Dans and Tian-Dtangs, the Tian-Hwans tend to have thin builds and tan skin - of the three, they also tend to be the shortest."
So the definitely not vague description of Tian tells us the following: males reach 5'6" only infrequently (infrequently is less than often).
Is what was meant that the males only reach a maximum height of 5'6" or a height of 5'6" or taller.
For the females what do you consider barely breaking 5 feet? 1 inch? 2? 3? less than 4? less than 3?
Ulfen:
ISWG: "Most Ulfen are quite tall, with men starting at 6 feet and the women just a few inches shorter."
ISR: "Men and women alike often exceed 6 feet in height."
What do you mean by quite tall. Is 'quite tall' the same height as 'rather tall' (Garundi) or is one taller than the other - and if so which do you consider the taller of the 'quite tall' and 'rather tall'?
Regarding the ISWG description: all male Ulfen start at 6' or that most male Ulfen start at 6 feet? What do you consider a few inches (or which range do you consider a few inches)?
Regarding the ISR description: standard female humans (from the core rulebook) have a maximum height of 6'1". - often (40 to 50%). So based on the description and the standard height range for female humans - about half of Ulfen females are exactly 6'1" with the remaining half being within a range that is either A) only a few inches shorter than 6 feet or B) the rest of the standard range for female humans (4'7" to 6'0").
The average height of the Golarion human ethnicities has already been hard-coded from the physical descriptions that have been officially published in the Inner Sea World Guide, Inner Sea Races and (to a lesser extent) Dragon Empires Gazetteer.
A suggestion for future books if you want to not 'hard-code' average racial/ethnicity heights: Use descriptors such as 'some' or 'many' instead of words like 'average', 'most', 'often' (as these three words 'hard-code').
According the core rulebook, a player (RAW) does not even get to choose the height and weight of their character but is instructed to determine their character's height and weight by using the Random Height and Weight Table. This means by using the standard (and only officially existing) table that many results do not properly align up with about half of the Golarion human ethnicities. Hence the request that an official random height table for the various Golarion human ethnicities is a very reasonable (and logical) request.