Regarding the Speed Force lightning thing.
Its not actually a new thing, but it is used wrong from the past canon.
I think Older Than They Think needs to be included for added clarification; ideally something like this:
Older Than They Think: Though it is new and a complete Ass Pull that the Speed Force can be used to make lightning blasts/explosions like that, this is something that the Negative Speed Force (IE, the Dark Side of the Speed Force used by 'bad speedsters') is shown to be capable of in the Flash Rebirth comics. As well as that, The Flash (2014) has depicted Speed Force users being capable of 'throwing' their lightning as an offensive attack, and it was likely this that gave Tom King the idea that Speed Force lightning was actually harmful (in the comics, its not actually lightning, but a visual effect of their interaction with the Speed Force), possibly making it a dark case of Ret-Canon.
Also, Ass Pull needs to be changed to note this, though the Speed Force lightning point needs clearing up entirely to remove Natter.
Possible replacement entry:
The massacre being caused by an electrical storm from Wally's Speed Force connection comes out of nowhere, as this is not something that the Speed Force has ever been shown capable of doing. They could have explained this by noting that the Speed Force was broken (as shown in Flash War), or by having Wally's trauma connected him to the Negative Speed Force, which is shown as being capable of such displays of chaos (Barry Allen, when corrupted by it, actually caused a similar display but was fortunate to avoid causing casualties). Acknowledging either prior to the reveal could have left the revelation something that a fan could actually guess, but instead it just ends up being something fans couldn't have possibly seen coming.
Regarding the Speed Force lightning thing. Its not actually a new thing, but it is used wrong from the past canon.
I think Older Than They Think needs to be included for added clarification; ideally something like this:
Older Than They Think: Though it is new and a complete Ass Pull that the Speed Force can be used to make lightning blasts/explosions like that, this is something that the Negative Speed Force (IE, the Dark Side of the Speed Force used by 'bad speedsters') is shown to be capable of in the Flash Rebirth comics. As well as that, The Flash (2014) has depicted Speed Force users being capable of 'throwing' their lightning as an offensive attack, and it was likely this that gave Tom King the idea that Speed Force lightning was actually harmful (in the comics, its not actually lightning, but a visual effect of their interaction with the Speed Force), possibly making it a dark case of Ret-Canon.
Also, Ass Pull needs to be changed to note this, though the Speed Force lightning point needs clearing up entirely to remove Natter. Possible replacement entry: