We do need, among other things, the sum of all Wikipedias. :)
A shared commons, wikidata, global templates, abstract WP! are all ways to get there. The suggestions in this article are not...
In particular, as long as reliability and verifiability and research norms are siloed by language -- with the barrier of translation making it much more difficult to parse and evaluate claims made in a mutually incomprehensible language -- articles about a topic T in language X will depend on reliable secondary sources in that language about T.
But we can move towards making this more possible, with
- better on-wiki / inline translation options [G! Translate is a step in that direction, but only one]
- better options for multilingual review and consensus [some languages and Meta have tried some versions of this in the past, so far w/o great success]
- better translation-linkage tracking between articles: indicating which parts of article in one language are synched/branched from parts of the same article in another language. [there is research + practical literature on approaches to this in other media]
- (many more...)