What's always bugged me about OBIS, is that some bandits (the worst offenders being the Iron Bloods variety) had their heights set to values like x1.2 and that meant I couldn't get any headshots on them, especially as I'm using Archery Locational Damage. The arrows just flew straight through their heads like nothing happened (the only way I could get a headshot was by aiming at their necks). This patch reverts the height values of all bandits to x1.0, with no extra esp so just install this with your mod manager of choice and overwrite the original OBIS SE.esp

A note that you will need a new save for the changes to take effect, as heights of NPCs are apparently baked into your save.

Strongly recommended for OBIS bandits appearance: NVICO (+ OBIS Patch included in Visual Compatibility FOMOD)  

Strongly recommended for archery in general: Skyrim Arrow Overhaul (that's where the bodkin arrows in my screenshots come from)