I would prefer it to be open now. The pyramids, temples, etc. will be ransacked (like Matt had said) in a matter of seconds. Which would make the waiting worthless. Plus, I've seen the current status of version 1.3. I have not found one pyramid/temple once yet. The biomes in version 1.3 are much bigger, so it would be harder to actually venture off and find a Jungle biome (I believe that is the only places these temples spawn).
I would suggest to add the plug-in that Toad had on his server. That one wand/magic thing. That was a really nice addition to the server which made it pretty fun.
Also, how many total OPs will there be on the server? I remember you saying that you would want more than yourself as an OP.