&gt; For 100% of the XML feature-set I don&#x27;t actually know of a viable alternative.<p>Real problems rarely need 100% of the XML feature set to solve. The breadth of the feature set is why there are lots of problems for which XML is a <i>tolerable</i> solution based on its inherent features (which in turn is a big factor in why it has such a large ecosystem), but they often don&#x27;t make it the <i>best</i> solution (especially before considering the ecosystem, which is important in choosing a tool, but not a reason to avoid developing a new alternative, since any new alternative is going to start with an ecosystem disadvantage, but with adequate inherent value should be able over time to gather an ecosystem of tools.)