Personally, I would make sure to keep the one with the giant rolling "Indiana Jones" ball - that one's a load of fun.
As for the dragon fight - I agree it seems a bit boring. When I revamped the hall for my second level party, I swapped the white to a blue, then de-levelled it a bit - blue dragons are more interesting, IMHO, because they really spread the damage around, which to me is a lot more fun than just hammering on one guy.
In my own revamp, I dropped swapped the first encounter for one with a mix of kobolds and some spitting drakes (the stable), I dropped the Tomb entirely, and I changed the skull-skull one (which I found the "skull skull thing" kind of stupid) to have a scything blade trap instead.
The ball one I left pretty much as it was other than adding some kobolds to make it more appropriate for a level 2 party.
And then the dragon, as I said, I made a blue and dropped it a level.