There are many debates about puerh definition. Here are some biggest ones. Most of these debates not only exist among ordinary tea drinkers, but also among tea experts and senior tea professionals. It seems that puerh is so complex that it's almost impossible to clarify it with one definition, one interpretation or one straight-forward view. For each of the following debates, there are many protagonists and antagonists. I believe it's important to be aware of them, because sometimes people have to agree to disagree. When we see exactly opposite opinions on puerh, probably neither is ridiculous.
Debate 1 - Is Modern Shu a puerh?
According to 2008 National Standards (which was carefully made and supported by many people), Modern Shu is one type of puerh. But there are also many people who strongly against counting Modern Shu as puerh, because it didn't exist before 1970s, and by inner character, it is much closer to various other type of Hei Cha (Black Tea, which, as a Chinese tea term, is post-fermentation tea. Not the same as black tea in Western tea terminology.) than to Young and Old Sheng. (my notes: I like Sheng a lot more than Shu. So I sympathize with this view.)
Debate 2 - Is young Sheng a puerh?
This may not be as big a debate as Debate 1, because no matter how much you argue about a young Sheng, some day it can possibly become an old Sheng. But there are people who strongly object that young Sheng should be called a puerh. Their major reason is, before a young Sheng gets aged enough, it's not puerh yet. It doesn't have the inner characters of old Sheng, and young Sheng doesn't have the same health benefits of both old Sheng and modern fast-fermented puerh Shu.
(my notes: I have less sympathy for this view, because there can hardly be a well-defined standard about how old a Sheng must get in order to be called an "old Sheng". But I do have some sympathy for it, because obviously, puerh factories benefit from blurring the boundary of young Sheng and old Sheng. This makes people, including me, suspect how much the 2006 and 2008 puerh Standards were influenced by the "puerh industry".)
Debate 3 - Does Shu mean modern fast-fermented puerh product, or does it include both the modern fast-fermented puerh and old Sheng?
This debate is reflected by Definition 5 in "What is puerh? (1)" - Da Yi's definition. Some people believe the modern Shu can never be similar to an old Sheng. Some other people, including Da Yi people, believe old Sheng will share similar characters with modern Shu. (my notes: this view needs to be tested by time and research. It may or may not be true. But obviously Da Yi's current interpretation is helpful for them to sell both young Sheng and modern Shu.)
To summarize Debate 1, 2, and 3, there are three different views:
1. Both puerh Sheng (of any age) and modern fast-fermented Shu are puerh. This view is consistent with 2008 National Standards.
2. Puerh Sheng (of any age) is puerh, but modern fast-fermented Shu is not.
3. Old Sheng and modern fast-fermented Shu are both puerh, but young Sheng is not puerh, YET. Within this group, some people believe that young Sheng should be called "Yunnan Sun-dried Green Tea" instead. Some other people believe young Sheng is an unfinished product, and is not ready for drinking/sale at all. (my notes: Even if it's not a final product, probably we can still buy them and store them at home. I believe these people's point is, price of Young Sheng should be that of an unfinished products, but nowadays there are too many expensive, upscale Young Sheng. Meantime, I can understand that these people's another point is, once factories sell you young Sheng, they are not responsible for the future of it. So if the young Sheng doesn't have inner quality to be well-aged, it's factories' gain and consumers' loss.) Supporters of this view say, "Although chicken is from egg, you can't call an egg chicken." Ultimately, name is not the most important. People's concern is, if the "puerh industry" attempts to sell an egg for a chicken's price, it's too much value inflation.
Debate 4. Can Hei Cha products from provinces such as Guangxi, Sichuan and Hunan be counted as puerh? Or, can puerh be categorized as Hei Cha?
Actually this is more of an ambiguity and not as much a debate. Most people agree that puerh is very much different from Hei Cha from other provinces. In tea market, most Chinese sellers wouldn't call Hei Cha from other provinces "puerh". But some Chinese tea books and articles (most of them don't focus on puerh, though) put Puerh under the category of either Hei Cha or Post-fermented Tea. In contrast, an interesting phenomenon is, some western tea articles and sellers would put Hei Cha (such as Liu Bao Cha, Sichuan Brick Tea, Hunan Brick Tea, etc.) under the category "puerh". I guess, listing Puerh (instead of Hei Cha, or Black Tea) as one of the six general categories of tea has something to do with a historical terminology dilemma. In Western tea terminology, the term Black Tea is already adopted for the tea genre which is called Red Tea in Asia, and so far in the West this tea genre is the most popular, best-known and most widely enjoyed one among all tea genres. Therefore it's barely possible for tea sellers to give consumers a strange name to their familiar tea, and use the familiar name "Black Tea" to a tea category that is still strange to them. Sometimes, what a seller wants the least is confusing buyers.
Debate 5. How proper is the geographic patent for puerh? Should the name puerh be restricted to products from Yunnan province only?
The Geographic Patent for puerh started from the 2006 Yunnan Province Standards for Puerh. But as a province document, it doesn't have regulation power on products of other provinces. But once the National Standards for Puerh came out in 2008, it has become illegal for products from other provinces to be called "Puerh". Although puerh originates from Yunnan, Guangdong province has more than 100 years of history of producing and exporting puerh products. Some people argue that the Modern Shu technique is largely from Guangdong. Therefore many people believe it's unfair to forbid Guangdong products of the similar technique to be called "puerh".