I would say that the concussion is the crux of the matter.
Concussion led to Liverpoole loss in final led to supporters blaming Karius leading to pressure which effects future performance.
This attitude/argument is exactly what drove me to my lengthy post a few pages back in the first place, so apologies that it wasn't fully balanced.
The myth on here that Karius was flawless or even excellent prior to his concussion and it was only the mistakes which followed that have led to question marks over him is astonishing and, for me, disingenuous.
It might have come across that way on here simply because any Karius dissenters were drowned out by a sea of numbers and passive or occasionally outright aggression. But the interest and links to Allison were real. And in reality there are plenty of Liverpool fans who were unconvinced by him. Now undoubtedly a lot of that had to do with his first spell as number one at the back end of 2016. I've acknowledged that I think his second spell at the front end of this year was undoubtedly better. Does that mean it was good enough going forward? Not in my opinion.
Numbers are a funny business. They certainly have their place in football. The issue with them, though, is people tend to only like them and use them when they support their arguments/biases. Numbers apparently aren't applicable to Gini Wijnaldum, for example, because so much of what he does 'can't be measured'. I have sympathy with that argument, even though I do have reservations about the player's general impact on football matches. The issue comes when that defence isn't applied equally to every player, or positive/negative numbers for other players are taken as gospel.
Back to goalkeeping, one of the best studies I've seen in recent months was by Sam Jackson of World In Motion. I posted his graphs in the Progress thread a couple of months back (snip below), or you can still find them not too far down his Twitter feed. Fair play to the guy, he watched every single save, every single piece of distribution, and every single piece of 'sweeping' by every Premier League goalkeepers last season and rated them accordingly based on a number of metrics.
When you combine all of this with Babu's data on dealing with crosses, where both Karius and Mignolet came out well, I essentially think the only major difference between Mignolet and Karius is that speed. I think both are decent goalkeepers, with Karius better suited to us, but like a few other areas of the pitch, they are definitely upgradable in my opinion.
In terms of our goalkeepers overall, neither came out brilliantly, but neither came out horrendously either, which is about what most people would expect from the eye test I would imagine.
The interesting thing for me is that Karius and Mignolet really weren't far apart on every measure: shot-stopping quality & consistency (Karius marginally better), Distribution (Mignolet marginally better), Sweeper-keeping (Karius marginally better). The same applies, IIRC, to Babu's study on how they deal with crosses.
It was just one study of course. But ultimately, from what I have seen across the board, the idea that all or the vast majority of the data point to a brilliant - or even potentially brilliant - goalkeeper in Karius seems to have only snow-balled on here I would say. Sam's study was talked down by a few as being too subjective. That was probably a legitimate point, but equally I'm not sure why an analytics professional would undertake such a lengthy study dishonestly, and you could make that argument for a lot of data out there. And it's not as though Karius came out badly! Like Mignolet, he just didn't come out brilliantly either.
It kinda just supported my viewpoint that they're both a bit 'meh' in slightly different ways, and a team of our standard really needs a goalkeeper with one or two outstanding qualities (whether it's sweeping/distribution like Ederson, or shot-stopping like De Gea), even if he also has one or two weaknesses like our current incumbents.
