[masklinn]

I largely agree. XPath 2.0 started the downwards trajectory and XPath 3 made it worse.

The things XPath 2.0 and later do improve on XPath 1.0 is the "standard library", most of exslt got standardised in 2.0, and new useful functions got added in later revisions (e.g. contains-token from 3.1 is XPath finally adding the ~= operator from CSS).

Here's the deal though: it should be possible to add most functions without updating the rest of the engine (indeed the majority were originally developed for 1.0). I think some of the functions are designed to work with and around types, which would not be useful in 1.0.

[benibela]

There are other useful things besides functions

Sequences for example. In XPath 1 the query returns a set, so the output is always in document order. When the document reorders things, the query output changes, and you can never get the original output. In a sequence, the query can output anything in any order