That wouldn't improve it.
The problem is not how in the access database the data is stored, one table is as good as another, the problem is that access can't cope with the amount of updates required, also each time a delete or update happens access keeps a copy of the old data slowly making the database grow to an unacceptiable size.
Just imagine if just 5 poeple are on the board at once, each click in the forum would require a database update, if they each only look at 5 posts in 5 minutes this would require at least 10 updates, if there are constently 5 people on the site over an hour this would be well over 100 database updates and thats not including the main page and pages listing the topics.
The only way to make it work for access is to move the tracking for the active users away from the database, using something like application level variables, this then would add quite a bit of overhead to the server, most hosts don't like the use of application level veriables becuase of the amount of server resources used (this is why many ban chat room software as most work in this way) this could lead to many web hosts banning Web Wiz Forums from their servers.