There are a few "features" of VBulletin that I don't like as well as UBBThreads. Both involve the post title bar. One is not showing the post date like you have pointed out. The second is not showing who the reply was made to (I view in the flat mode or linear mode as they call it, so, it forces me to change modes to see who the reply was intended for).
I am not sure if either of these can be "fixed" or if they are simply "features"! I have made inquires but haven't heard back. Also, I haven't come across a site that uses VBulletin that has these "fixed" so I have a feeling that they can't do that.
So far the best way I have learned to deal with the post dates -
1) Read all the threads that I care about and do what LOCUS said - "Mark all threads read". This resets you to having nothing "new". It is also available in the "Quick Links" drop box.
2) Use the "Quick Links" drop down box to select "New Posts". This now only shows you threads with new posts since you last logged-in.
3) When viewing the threads, the new posts are identified by an orange box in the upper left corner, so, simply scroll to the first orange box if you have the display showing the oldest post first OR to the last orange box if you have it set to show the newest post first (the mode I personally use). You can change your viewing preferences in the "User CP".
Hopefully this will help you to sort out what you want to view and what you have already viewed!
BTW....this software is much more powerfull than the old and has a lot of cool features. For example, when you are reading a post there is a small dot to the right of the posters name. If it is green, they are on-line. If it is blue they are not.
At the bottom of the "Forums" main page there is a list of current members logged on and who has logged on that day. If you point your mouse at a member that was logged on earlier in the day, the mouse over function will pop up a box that shows when they were last logged on!
Adding pictures and managing them is easier for most members as are the Avatars and Profile signatures, etc. Not to mention the very powerful moderator and admin functions. So, overall, I think it is a major improvement.....we just have to get used to it!