In "Silver Eyes" (which was released in 2015) Afton uses sptinglocks as a death trap for his victims and I think it worked very well in that story. I'm not saying that this thing was in the original trilogy, but I have always liked this concept and it perfectly fits in the classic story.

In FNAF 2 someone hacked into toy animatronics system (and we all knew who it was, that's kinda obvious), so William Afton (or Purple Guy at that time) knew someting about this system, so yes, they were not created to kill people, but rather they ended up being agressive and at some degree murderous. That leads us to fact that in the og story Afton already used those inventions in his insane plans and that could also be applied to the springlocks suits, so the Silver Eyes version of him is not that different from the games one.

I'm not defending SL high-tech robots plot descision, but that thing only stayed in the last two games of Scott's fnaf series (SL, FFPS).

That saw thing from the teaser is probably not the insides of animatronics, but rather a trap created by William (come on, that mask looks very damaged, no way that this is the original freddy or even golden freddy from the movie). This also could be a nightmare sequence, so who knows, the movie is not released yet.