On some patterns I prefer diagrams, but only if they are good enough at explaining the step. Sometimes I end up staring at them for ages because they just make no sense to me. Same with actual photos, if they aren't clear enough, then I don't find them helpful! Also, I think I would like it if each step has it's own picture, as sometimes it's just the tricky steps that have pictures and it would be easier to see the full process with a picture for each step.
Re: fabric requirements, I like to have a picture of how every piece of same fabric has been cut out of the requirements, as i'm sure everyone would do it slightly differently, and it would be very easy to get to the last piece and not have the right cut leftover because of the way the rest has been cut out. (hope that makes sense!)
I like a very clear layout for instructions because I have an illness that makes concentrating difficult, so having huge chunks of text is a no no for me.
That's about all I can think of for now, if I come up with anything else, I'll be back!
If you'd like feedback on your pattern once you've done it, I'd be happy to help :-)