I discussed this with Skalman this past Feb when I met him in London, where he (shouted in pub) the jist of this problem to me.
Since then, we have been looking into the reasons and support cases for this issue.
But a few things I have to say to be sort of a devils advocate:
Yes, its really irritating that the malls do shut off during events, but the ratio of event times and normal shopping times makes it less prominent.
Also I can see an advantage of the malls being shut off during the event, simply to decrease user load during events. Events such as Equipping Calypso which can run up to 30+ people all hunting as fast as they can can sometimes lag the server pretty badly and to have a few dozen people trying to access the mall could present an even worse problem. Of course, a stronger server would do the trick, but of course we won't consider that as an option.
Emerald Lakes has a lot of advantages. Lower price mall maintainence, higher item count, two teleports, a land area dedicated to to the mall, a container nearby, etc etc. It seems almost expected that the land area would have some flaws and some set backs.
One thing I definitly DO agree with is this: if the mall is going to get shut off, then I agree, MA definitly should look into turning the mall itself into an event area for PVP.

I think this would be great fun and plan to discuss this with Rob in the coming days. Here's hoping and I've got my fingers crossed!