Yeah, this would be a great option for admins to have an use, but I could see this being abused. Imagine an admin who was a particular perk, and decides to troll people by having all the tier2 and up weapons, blocked (not counting his perk's own weapons). What is everyone going to do? I suppose leave, but thats just annoying playing on a server an then have an admin who does stupid stuff like that.
As for comparing KF to L4D and L4D2, those two games are just too different to compare, and honestly, I love l4d for it graphics, and l4d2 because of its mechanics. Not to go too off topic with things, but the one thing that makes l4d2 better than KF, is its ease of ability to customize all the skinned items in the game, and to used modified weapons. Example of various "game balancing" modifications, was pistols with limited ammo, all weapons have a smaller pool of ammo, and damage gets scaled up or down, based off the type of weapon. However, what makes KF better than L4D2, is that its attention to details to the weapons, are amazing. The animations, sounds, and detail work is superior to l4d2.
Back on topic, weapon removal would be nice if they were fair about it, but if one person says that the IJC weapons are unfair, while another person says that they are fair, neither one of them are correct or incorrect, because its a matter of opinion.