The fact the jury took ages means nothing really. The problem they almost certainly had is the point about "beyond all reasonable doubt".
They clearly think she passed that threshold on a number of the murders - but crucially not all.
So there would have been some argument in the jury room over those other cases and whether they are sure there was no other explanation for the deaths of those children and/or that she was the only one who could have been responsible for them.
That alone could have caused the deliberation to be lengthy - whilst they were also firmly convinced on a number of the murders.
In terms of 'evil', I think the desire to other killers is really compelling. 'They are not like us'. It's protective in a sense. Yet the very point made during the Nuremberg trials was 'the banality of evil' and how utterly normal and average those in the dock were. It was circumstances and opportunity that led them to do what they did.
In the Letby case you have a scenario where, even when she had people saying she was the problems, the hospital trust stepped in and said she was effectively untouchable. So she did more whilst being watched, because she could. It's a power trip at that point.
Reading that criminology article upthread about healthcare killers it's also fascinating in the sense that, unlike other forms of murder which are done mainly by mean, the profile is different. It seems to be much more evenly split between males and females - and that in itself is something that is shocking. Why is that the case? It is environmental in some way and that being exposed to the illness and death of others somehow has an impact? It also said that about half seems to have mental disorders. Conversely that says that half don't and are classified as sane. The feature that seems to mark Beverly Allit as different to Lucy Letby is the former was determined to be ill.
Given all this, I do think the hospital needs investigating because it was hung up on its reputation and had a disbelief that someone could be doing this, despite the data being damning. Why was there such a high death rate? The hospital management if they cared about their reputation should have been all over that. The fact the consultants all grouped together to say that 'nice Lucy' was giving them cause for cause coupled with the death rate is the ultimate issue.
The idea that someone normal could be doing this, is at the very heart of the issue - and of public shock. But that's precisely why she did get away with it for so long.
And the hospital gave her the opportunity to do it even more. The criminology article says about how health care killers seem to be addicted - they do the same thing over and over again. It is almost like they can't stop themselves. That note that was found, in this context almost reads as if Letby wanted to stop or be stopped but wasn't. If healthcare murderers are unchecked they have some of the highest rates of murder there are. That's what hospital management should be aware of in terms of a pattern and safeguarding. Dodgy death rates need a follow up. It's it's poor practice or a dodgy person. Either way that's the responsibility of management to be keeping an eye on.
Of course healthcare murderers shock us more because the job of these people is to make us better not to kill. But also the sex of the perpetrators can make us all feel more vulnerable and that pattern of murderer's usually being male doesn't fit healthcare murderers. So again that defies our expectations and feelings of comfort.
We want to believe in the bad guy who is obvious because then we can spot him easily. That makes us feel safer that it is something we are immune to and we have control over. We can avoid the situation by 'making good choices about who we associate with and where we go and how' - it's the 'she shouldn't have dressed like that' mentality that blames the victim.
As I say, the idea of a murderer being normal, nice, female and in a caring role over people when they are most vulnerable is the most terrifying dynamic of all. Especially if the victims are children. It's all our nightmares at once. Because it goes against every bit of the way we've been conditioned and therefore undermines our trust in others to the highest degree. But that's precisely where hospital management should be in terms of safeguarding the public - looking for the arrogance of incompetence and the banality of evil.