My change does not remove any of existing “stimpacks”, neither change their effects, since none of them interact with bleeding. If there would be something feasible that would act like that - I’m thinking like Zagusting in Escape from Tarkov - I would add it, but nothing such as this comes to my mind.
All other first aid items remain, but their effects were brought in line with the change itself. Previously the quality of bandages, hemostatic powder, etc. were statistical, but with 0/1 effect at the end - they had certain percent that they would work, and when they did, bleeding stopped all in once. Now they have certain quality measured by how much can they can reduce bleeding. For example a bandage may stop small bleeding, but for a large bleeding you would need two (or more) bandages. But if you have only one - it would still reduce the bleeding.
There are new first aid items - adhesive bandages (band-aids) for small bleedings and scratches, that come in bulk; and tourniquets - they limit the effective bleeding but don’t close the wound - it still needs bandages to be closed for good.
Sutures are a very good idea for implementing. Thank you for mentioning that. I’ll definitely put them on my To-Do list. I believe that non sterile sutures should carry the risk of infection, but that by itself is a mechanic that can be implemented.