Eh, the issue is that there's no flight AI like there was in Morrowind. Creatures that do appear like they are flying are actually "standing" on the ground. Another issue is that creature AI requires areas that they can move on to be marked as such and that area is "cut" around objects like rocks, fences and such and creatures/NPCs can never go "over them". There's also no AI for jumping over obstacles or scaling the walls. The movement that is in game is the best it will ever be.
Had the same issue back when I had AMD card, no mods, but the issue went away when I disabled anti aliasing. Make sure AMD isn't forcing AA via its control panel or whatever it's called. It doesn't happen on nVidia cards, as far as I know.
Are you kidding me??? Same issue started happening to me just yesterday. Disabled all mods and it still keeps happening. Never EVER did that happened to me. It literally started happening yesterday without changing anything in game.
Look for NiMaterialProperty (it's inside of NiTriShape or NiTriStrip) and inside there's Emit Mult as well as color of emission you can change (by default it's black), just below Specular color (you can't change specular color btw).
Slides are bink videos. To have courier wear last armor they had equipped before ending slides would mean making huge amount of videos for all possible armor combinations, not to mention mod added armors. So, it's not gonna happen.
Placed Impact Object is a new addition to Explosion form in FO3 GECK added by Bethesda when Broken Steel DLC was released. If you don't have it in FO3 GECK then you probably haven't installed the 1.5 update for GECK.
Turning off vSync will uncap your fps, not cap it. Use something like this to actually cap FPS: https://www.guru3d.com/files-details/rtss-rivatuner-statistics-server-download.html or if you have nvidia card, you can use nVidia inspector.