You wouldn't be able to do views by day, no. vBulletin doesn't store views by day, just a running total of views. You'd be better off tracking things in Google Analytics. The views do not exclude bots anyway.
You could run a query to get the most viewed threads ever though:
Code:
SELECT thread.title, thread.replycount, thread.views, forum.title AS forum
FROM thread
LEFT JOIN forum ON thread.forumid = forum.forumid
ORDER BY thread.views DESC;