And in the Spanish version there may also be translation errors which the original English version will not have Xabier Armendaritz
This is FUD, but I understand that posture, since there were years ago many errors, indeed. But I (and several others) have been working hard to correct those during the last years.
I suspect (not being a Spaniard) that there are political reasons for not wanting to change the fallback to Spanish, similar to the recent change in Belarusian-language wikis by which the fallback to Russian was removed. I would personally favor not doing any changes in this regard.
"similar to the recent change in Belarusian-language wikis by which the fallback to Russian was removed" That's Ukranian, not Belarusian, see phab:T39314
10% of Basque don't speak spanish but 100% of them studied english as a second language. Besides, I prefere to have as a reference the source language much more than another translated one. Therefore, I thing that matching a small language with his dominant language (spanish/french), it's not a good idea for the development of the small one. -Sator (talk) 23:23, 1 January 2017 (UTC)