But it's not an inconsistency; it's a regional (national, actually!) variation. Every single language has those, no exceptions. What's different about English (and perhaps some other languages? Japanese has a very similar pronunciation to Spanish, and pretty much consistent too) is that it has inconsistent pronunciations even within a regional variant (or, indeed, baseline English... if such a thing exists).
And I have to say it's charming as hell. There's a cliche in Spain that the Argentinian guys get all the (Spanish) girls, and I can't blame them, even I find it awesome.