I will assume you mean the gunpowder skeletons, as that makes the most sense. First of all, they are fairly rare and easy to kill if you have some flintlock or eye of reach ammo on you, or with some creative pushing of other skeletons. They need speed to be viable skeletons, as without their speed they would be useless. I believe they are the exact same speed as normal skeletons, although they do not have the ability to sprint. Lowering the speed just means they will only get there even later and blow up all of the skeletons and you while you aren't looking, which would only lead to more complaints.