Mark, I've suggested a few things elsewhere that I imagine could be reasonably easily implement and which would improve things but I've had no response, so here they are again:
1. Relax the upper limit on attachment sizes. 1Mb is pretty small. This is a site for photographs. All seemed well before and, as Michael repeatedly observes, disk space is cheap.
2. Have the "Additional options" tab open by default when posting. Why not? It takes very little space and it's at the bottom of the screen anyway. Why force an additional click?
3. Fix the "insert url" button so that it works properly, as it did on the old site. The number of mal-formatted URLs which have been posted since the new software was introduced indicates that something is wrong (or that we're all idiots).
4. Restore the "your last visit was at" information: it's very handy for those of us who, like me, routinely use "show unread posts since last visit" to read the site (or am I the only one?). Similarly, putting that action into a button in the button bar would make life a bit easier.
I realise some of this is an attempt to persuade you to make the new board look and feel like the old one but what's wrong with that?
Jeremy