The problem with stats in DV is how stats are now earned yearly over time by all kids (xcept the ones existing at scenario start). Children gain 1 or 2 stat points every year from 1 to 14 (? Could also be 12... not sure): at least one in diplomacy, martial, stewardship or intrigue, and possibly a second stat point in the same or another skill.
This means they can (and often do) end up with a score like 10/8/9/8 -- which is superhuman.
Note that this is the BASE stat, traits can raise these even further. E.g. prodigy adds one point to all stats, and the completed education traits can add up to 4 points for the main stat, so a character with a good combination of traits in DV can easily end up with a score of 12 or higher in multiple stats, and I've seen scores of 18 and higher... which are so far out of the range of what the game considers normal that they become meaningless.
Events use stats for various means, often with 5 = normal, 8 = good, and 10 = super. If I were to re-weigh these to Deus Vult, it'd be something like 7 = normal, 10 = good, 12 = super.
That in itself is modifyable, but there are also hardcoded checks for these stats which are based on CK values, not DV. For example the demesne size limit, income, assassination chance etc.. These cannot all be modified.
I still hope that we'll get another Deus Vult (beta) patch which slows the rate of stat gain (for example by making the chance of getting two stat points in a year much smaller, and/or by capping it to the age range 2-12), but since Johan is busy with new Paradox projects this is unlikely.
Hence the stat lowering events: they are the only way to keep the game working at least a bit like it should.
The main problem with them is that they are immersion breaking. I wish I knew a better way to make them fit, but there just isn't anything like a board of education in the middle ages that administers standardized tests. If there was, I'd use something like the following as event title and text:
"Grading on a curve: This child's final grades have been adjusted in order to fit a normal distribution."