I've been reading about the latest RSS controversy for the past few days, and I think this post on the RSS-Public mailing list summarizes my thoughts as well as anything:
Being Ambiguous that way is a bug, not a feature.
Here's a question: I'm an aggregator implementor. Based on the spec being ambiguous in this area, I might allow for multiple enclosures, or only one – and if I pick only one, it might be the first or the last. What's the correct implementation, based on the spec? Don't bother pointing me to blog posts – opinions expressed outside the spec are just that – opinions.
The spec does not tell me what to do, so I make a call based on what I think I see happening in feeds I see. This in turn leads to other aggregator developers making it up as they go along as well – witness the list that Rogers put out awhile back, with the wildly varying behavior across tools.
That's a bug in the spec, and clarifying the spec would repair the bug. It would not be a change to RSS, any more than marking incorrect spelling on a student's paper is changing the language.