Is the inherent XPath/XSLT 1.0 data model better from the point of view of functional capabilities, or the data models of next versions (2.0, 3.0) of these language specifications?
XPath/XSLT 1.0 data model, focuses on having a well-formed XML document tree as part of the data model. Whereas, 2.0 and 3.0 versions of these language specifications, focus on having a flat sequence of data model items (like atomic/list values or XML nodes). Many of the XPath/XSLT 2.0 and 3.0 use cases, still focus on achieving well-formed XML document trees as part of the output of an XSLT transform.
Although, the definition of data models for 1.0 versions of these language specifications, is fundamentally different than 2.0 versions of these language specifications (one is a coherent XML tree, whereas the newer version is a sequence of data model items), the XSLT 1.0 and 2.0/3.0 transforms try to achieve the same end-result (i.e, an XML well-formed serialization of the data model instance).
I think, XSLT 2.0/3.0 brought sequence of data model items as a fundamental new definition of data model, because XPath 2.0/3.0 data model components need to be strongly typed at a granular level (aligning with XML Schema specification).
If we need, greater strongly typed process of achieving an end-result of the XSLT transform, we should select the 2.0/3.0 versions of these language specifications. Otherwise we should opt for the 1.0 versions of these specifications.
The 2.0/3.0 versions of these language specifications, have brought in newer XSLT language features, and also a vastly expanded function library. That's an advantage of using the XSLT 2.0/3.0 languages, than the 1.0 version of these languages.
At various times, I'm not desirous of too much strong typing (in an XML Schema sense) within an XSLT transformation process (because that involves, greater design effort upfront), and if my XML transformation requirements are simple I tend to opt for an XSLT 1.0 transform. I certainly go for, XSLT 2.0/3.0 options, if I'm not constrained by these factors.
