You may be interested in looking at the following greasemonkey script:

<http://www.gold-saucer.org/mathml/greasemonkey/>

It doesn't look as though it's been worked on recently but that doesn't stop it being usable. The basic idea is to overlay a simplified latex->MathML converter on top of a webpage.  Since it is a greasemonkey script, it is **entirely** user-controlled and can be applied to any webpage, arxiv or otherwise.

Of course, there is always the problem of non-standard macros in abstracts and I completely agree with the sentiment that abstracts should be 100% legible without requiring extra parsing.

(In addition to posting this answer, I am add my vote to the list of "to close" as I agree with the various sentiments on that line in the comment thread.  That I'm answering the question is not paradoxical since this isn't actually an answer to the question that was asked.  I'm not convinced that I would want to see the question to which this is the answer also posted on MO, but think that the easiest way to prevent it being asked is to answer it here.  I'm community-wikifying this answer not because I want others to be able to edit it, but to underline my opinion by forgoing any reputation for this answer (not that I assume it would actually get any!).)