Welcome back Ben,
About 1) We had some trouble making the single column resizing smooth enough (it isn't quite there yet), for the moment we'll keep it like this. There has to be some speed improvement first to allow several columns at once.
About dragging the column, you can actually drag it now, tap&hold on the header and then tap on Move. Give it a look
here. We'll improve the look&feel of it but for now the 'mechanics' are there already!
2) Yes, we'll probably add the cross for absent, but for interface consistency a double tap will toggle the status from present to cross and viceversa.
We're working on an attendance calculus column that takes into account the quick attendance icons but haven't figured out yet an intuitive way for the user to enable it.
3) Absolutely, we're preparing a settings screen in the iPad's configuration window to allow this minor tweaks (there will be more to come). Date formats are always a hassle! I never understood the month/day format but some people can't live without it...
4) I like the idea but usually when a date increment comes to mind, people need days/weeks/month's increment and this leads to some configuration issues. That, in fact, is why we put only the TODAY button on the column's configuration, in a today button we all agree. We'll work on it.
Thanks for your comments. We really take them all into account but we filter some things out at first until we find a nice way to integrate them. Having lots of options is great but we try not to end up suffering from bloated 'featuritis' and keep things easy for the casual/new user.