When I worked out that my little boy was a high needs baby it was such a relief to know that his fussiness and anxiety weren't my fault - I wasn't doing anything wrong. It's not about the label as such, it's about understanding that some children are born with temperaments that make it more difficult for their parents to soothe them; harder for them to settle and sleep; likely to find feeding difficult; highly sensitive to change/noise/light/new experiences...and the list goes on. There are ways to support a high needs baby and then toddler and then child...but for me the greatest gift was knowing that it wasn't just me! Here's a great article from 'The Fussy Baby Site' which should help you to be able to identify if your baby has a high needs temperament - you'll quickly know if this resonates with you http://www.thefussybabysite.com/high-need-baby-resource-guide/. I also highly recommend the work of Dr Sears on this topic.
Many of my clients have high needs children and I tell them that we can gently improve their child's sleep but that it generally takes longer for a high needs child to adapt to the change. We always want to be sensitive to the needs of our children, whatever those needs may be, and that is core to my sleep work.