Thank you for the feedback, it is much appreciated.
1) At the moment, setting a generator to 100% nulls is the only way. We have an item to look at this in a later version.
2) Like in 1, we understand this isn't great at the moment and we are looking at making it more understandable. However, using the other generators, such as RegEx, can provide you with this functionality.
3) On our numeric generators, we have two types of distribution. One is Random, the other is sequential. With sequential, you can set an increment value, this allows you to go 1,2,3,4,5,6,7,8,9 etc. If you look at the Business > IDs generators, you can see how we have used it. Does this answer your question?
4) Thanks, I've added a note onto the item that you have also requested this. It's useful to know where the demand is.
5) Like with 2, it would be more useful to have a generator which could do this. Two possibilities with this, one is write your own generator and upload it to CodePlex to share. The second, use a SQL Statement generator and as the sql statement use SELECT GetDate().
I hope this helps, if you need anything else please let me know.