I think we are sometimes too lenient on our tagging.
For example, a translator or type conversion shouldn't be tagged conversion.
The former whilst you are changing the input, it's not converting it's form, it's more than that. You have to take into account lexical nuances, my ex used to tell me how French had some funny sayings, that make no sense on literal conversions. So this is more than just converting
'Type conversion' also known as typecasting and coercion shouldn't be classed as a converter, only one of the names has 'conversion' in it... Casting the type isn't a converter, OP didn't implement the conversion, all the OP is doing is call a function. If we allowed this then we might as well tag ever question with this tag, they all typecast at some point...
Changing database schemas as far as I know already is part of a classification called database normalisation. And so shouldn't be called conversion.
I'm on the fence on data converters, such as 'music notation', 'to/from HTML' and possibly 'transpilers', as they are converting a structure.
Real converting problems
The above removed half of the items from the list, saying they in essence aren't converters, whilst they change things that's not enough in my mind to be classed as converting. Just for the same reason we say 'translate to Russian' not 'convert to Russian'.
However it leaves two types of questions behind.
I'm actually quite surprised that one of these groups haven't got a tag.
Also, these are specific conversion 'groups', so whilst they cover almost all the questions on that tag, they are specialised enough to not arise concern in the future.
From your list you have:
These are all conversions from a numeral system to, normally, another numeral system.
(With the exception possibly of, hex string to byte array)
I personally am shocked that we don't have a base or base-conversion tag.
Binary and hexadecimal converters seem like a common way to learn the numeral systems, (I'm not very educated, so I may be wrong).
But even so this has already gotten two tags roman-numerals and numbers-to-words which highlight that it's something people like to do, but can't classify as one thing.
I think making a tag for this is the best way to deal with the left over problem. And converting to the new tag would be easy enough as we can just alias the above tags to the new tag, as they are sub category's.
Possibly with the exception of base64.
This is also a common conversion task. With the increase in globalisation we come across notation, formats or even measurements that we don't normally use.
As a non-American, I have to times whatever the 'world price' (dollars) is by 0.6 to get a rough estimate on how much something is worth, or costs.
This is, mostly, the others of the on topic items on your list. And is also quite common.
Temperature and other measurement unit scales.
Metric, imperial and SI unit converters are nice.
datetime formats. Reading the date can be a problem: 5/11/15, 11/5/15 and 15/11/5.
Things where half the world can't agree, 1,000.5 or 1.000,5.
I think flat-out burnating this is a bad idea.
There are some questions that are to do with conversions,
but don't belong in the above groups.
The question for transliterating Japanese isn't translating. It's converting one way to write something to another. It's like converting Greek to the modern Latin alphabet, so 'a' to '\$\alpha\$', 'b' to '\$\beta\$'. Or Roman numerals to numbers.
And Converting IP Addresses to minimal binary formats as IP's aren't a numerical system.
Both are still valid converting questions.
However I don't think we should get questions where this gets tagged with the above tags. Like python with python-3.x and python-2.7.
Plan of action
- Create numeral-conversion.
Synonym base-conversion to numeral-conversion.
This is as people will search 'base x converter' for the tag, not 'numeral converter'.
Synonym obsolete tags roman-numerals and numers-to-words.
Leave conversions for a bit, to assert if it's still too broad.
If it is:
- Create a tag like localisation-conversions. But I think localisation is the wrong word.
Remove the tag from invalid questions, when they appear.