[Tagging] The saga of landuse=reservoir vs water=reservoir

[Tomas Straupis]

But prudent way would probably be to come with some rules on change of
tagging schema. Like:
* When tagging schema is too widespread to be protected against changes
* What benefits should new schema add in order to deprecate existing schema

Because otherwise this plague of deprecating existing widespread
schemas (water is not the only impacted area here) in order to bring
some dubious "benefits" will continue. Some people simply do not have
experience and do not understand what is the value of stability and
what are the actual costs of changing something which is already
widespread (for this I like to give an example of highway tag which is
was correct when it was created but is incorrect now, but we do not
change it for the same reason of stability and total cost).

P.S. Stability does not necessarily prohibit freedom of tagging.