Thanks for the answers, James.
If it is a standard search, the results for languages other than English will be quite poor and I am not sure how the Solr migration could help in that regard.
Image tagging with Wikidata items could be more effective for i18n. If there are already plans to make it happen, that is unknown to me.
About the gallery, maybe you could take a look to the proposed gallery and comments? ("Redesigning the <gallery> tag.")
http://lists.wikimedia.org/pipermail/commons-l/2013-June/thread.html
I like that bawolff's proposal is less gridded, but of course, that is only my subjective perception. Maybe there is room for collaboration there.
Things I missed in the VE's image gallery:
- a way of accessing the Commons file page
- a more clear highlighting (maybe slightly enlarging the image)
- double-click to insert
But other than that, for a first release it works quite well :)