kbaby, I am wondering the same. Dd was very difficult in almost every area: sleep, feeding, not being able to be put down/unsettled. Am expecting ds in a couple of weeks with bated breath.
I think if the first was a high needs one due to temperament (rather than a medical condition like reflux), then there is a chance that the second one could also end up with the same temperament.
In my case, dd got her temperament from her daddy. My MIL said all her 4 babies were difficult, but my dh was her first and worst!
I don't buy it when people tell me it was because dd was my first and I was stressed and anxious and baby picked up on it. NO - I am NOT imagining it when I say dd is hard work no matter what I tried. Why else would nurses on the maternity ward tell me how unsettled dd was? Why else would experienced nurses/HVs who tried everything to get my dd to take a bottle have to give up eventually? Why did the doctor who tried to examine her lying down (dd would not be put down) recoil in horror at dd's protests, thinking that there was something wrong?
But if I am fated to have a second difficult one, I am glad I have lived through dd's babyhood and learnt to parent harder. Go-with-the-flow, get a sling, put rest of life on hold as much as possible, ignore everyone else's advice, meet baby's needs as best I can and just wait it out.
Dd has blossomed into a most delightful, engaged and lively 3 year old.