You've hit the nail on the head. William not only had the same trauma as Harry in terms of losing his mother, but he had the extra burden - and I think that is how he perceived it - of being in direct line to the throne. Yes, he got lots of attention, but it must have been utterly stifling to be told from the year dot that he wasn't ordinary like other children and therefore needed to heed this, that and the other stricture. Most young children just want to fit in and be like other children.
But as
@Campagne says, even if Diana hadn't died when she did, I think his childhood was marred by his mother's inappropriate behaviour with him. For example, she not only allowed her differences with their father to be known to her sons, but actively encouraged them to engage, for example sharing her feelings. It's well-known that she'd confide her troubles to William and become emotionally distraught to the point she'd lock herself away and William would push tissues under the door to his crying mother. As well as parental alienation, i.e. bad-mouthing Charles, it's probable that William was left in no doubt that he was expected to take sides, namely with his mother. I guess Diana's famous silent treatment or some other guilt trip would have been the alternative.
It's bad enough for a child when their parents split up amicably, but when there's animosity, children can suffer horribly unless the adults behave sensibly. This wasn't William's experience and not only that: his parent's relationship breakdown was played out publicly and a lot of dirty washing was aired: tampon-gate, squidgy-gate, Will Carling, Oliver Hoare, James Hewitt etc. And poor bloody William was being used as a mini-adult throughout it all.
Putting aside the distress and confusion he must have experienced, children don't have the emotional maturity to understand the dynamics of all that
tit, and where they fit into it. What the
duck? By today's standards at least, it'd be considered emotional abuse. Thank goodness William was away at school a lot of the time.
I'm not sure how Harry fitted in to the scenario. Despite H's trauma about his mother's death, nothing much has been said about how H was influenced during the many years - most of his life really - of the War Of The Wales'. W and H seem like chalk and cheese, though it's reported that when W was very small, he was the more out-going and boisterous of the two. That changed when Diana sacked their nanny Barbara Barnes because she was jealous of W's love for her. Apparently after that W became much more introverted. William seems more serious, thoughtful and empathetic. H isn't any of those things and I don't think he'd have been able to fulfil his mother's emotional needs. Coupled with H being younger and used to not having to toe the line because he wasn't going to be king, I suspect H got a free pass and William got the
crappy end of the stick.
How difficult it must have been for W to carry all that distress, guilt and ambivalence throughout his childhood and later years. Happily he seems to have benefited from whatever therapy he received: the poor bugger must have had to work hard at it though. And as
@Campagne says, with Kate and her family, and now Kate and William's own family, W must feel like he's safely in harbour.
Here's a wee snippet from when I was in my late twenties / early thirties and all the drama described above was going on. At the time, I lived in Kensington and worked just off Kensington High Street. My hairdresser was within spitting distance of Kensington Palace, and during my many hours in the salon chair with my bonce covered in foils, me and my hairdresser had plenty of time to chat, often about the contents of that week's sleb mags such as Hello! We'd put the world to rights on people's clothes, hair-dos and choice of partner, as well as the latest Charles and Diana goss.
At that time Diana was perceived in the press as the beautiful wronged woman, while Charles' name was mud as was Camilla's. The hairdresser's and my convos were along those lines and on one occasion the boys' names came up and I said they were better off at school during their parents'
tit-show. The hairdresser lowered his voice, glanced around the salon, and told me that some of his clients worked at the palace. And that one of them had mentioned that William's school - he was at Eton at the time - had told the palace that he was often in a great deal of distress, crying and saying he hated his mother.
That poor, poor wee boy. It probably sounds sacrilegious but in some ways it's a good job Diana died when she did, otherwise the damage to William could never have been unravelled.