The 30 second delay between worldhops is not a technical limitation, it is a now redundant method of stopping people from constantly buying out all the runes in shops (among other things, but that was the main one at the time) using custom browsers that had auto-login features (RHQ's Xplorer in particular at the time). As shops no longer sell runes vastly below market price and have an infinite stock this is not exactly much use anymore.