A number in the column so far to the right where the useless information is that usually is ignored anyway... not good. A symbol says more than thousand numbers
. Also, two different coloured backgrounds for unread topics, for a total of 4 colours: why so complicated if a simple symbol like in the previous board - or in any other good board on the web - does is better? Just making it different for the sake of differences does not mean making it better.
If you want to give as many informations on a quick glance as possible, they need to be as simple as possible. If you can get these informations in a quick glance, without having to start conscious thinking - like, now which 2 colors of the 4 were for new topics?? - it is much quicker and more relaxing to read.
Also, an individual choice between preview or post directly when submitting Messages, like before with 2 simple buttons, is much better than a general preference.