1) Store enderpearls more compactly in block form (this idea is old, so this suggestion is more about part
2) Stop people from teleporting where they aren't supposed to
This would be accomplished with a new block called the Ender Ward. The Ender Ward is a glossy greenish block crafted out of 9 ender pearls. It would looks rather attractive, and since the idea of an "Ender Block" for storage purposes isn't new, you can Google that and find many renderings and mods that people have made that show what the Ender Ward could look like.
The Ender Ward isn't just a decorative block though. It's also defensive mechanism, to stop intruders from getting into forbidden areas using teleportation. Each Ender Ward projects an invisible no-teleporting-allowed field in a four block radius around it. This forms a 9x9 cubic area, with the ward block in the center, that people and endermen cannot teleport into. The no-teleporting-allowed zone extends through solid blocks, so you can hide the ender ward under the floor or in a wall so nobody can see it.
If a player tosses an ender pearl into a restricted zone, no teleportation occurs and the pearl returns to their inventory.
If an enderman tries to teleport into a restricted zone, they'll immediately teleport again somewhere. However to prevent this from being exploited to build overly easy enderman farms by covering the entire landscape with ender wards except for a harvesting area, if the second place the enderman tries to teleport is also restricted, the enderman will tolerate it and stay there. So this is useful to reduce the risk of an enderman appearing inside your house, but it can't be used to block off huge areas of land.
Being able to restrict teleportation in this way could be very useful for a wide variety of purposes. Server owners could use them to stop people from teleporting over walls into restricted areas. Adventure maps could use them to limit where ender pearls can be used, for example a Portal themed adventure map where you can only teleport onto certain surfaces. Redstone engineers could use them to stop endermen from teleporting into sensitive machinery, and possibly stepping on a pressure plate or picking up an important block. All in all, I think it would be an insanely handy block to have, in addition to being a compact way to store your ender pearls.
This is an awesome idea. I hate ender pearl glitchers, and lining your base with crafting tables isn't exactly ideal.
Digging a pit under your base and filling it with lava offers a much more amusing effect, along with not disrupting you if you have to fight inside your base...
Anyways, I 100% support. Completely balanced and definitely something that I could use on a regular basis. The one issue I can see is that even with the restrictions, it's still possible to farm endermen with these, but farming endermen is easy enough already.
One potential problem though, is that if you're trying to protect a large space from endermans, it will be difficult to hide the Ender Wards. If you're trying to protect a small area, it will be easy to hide the Ender Wards, but it would also be easy to make a 2-meter ceiling.
But for players, it should work either way.
Also, what if an Ender Ward also prevented portals from working? And Ender Chests?
Could it interrupt teleports if the enderpearl passes through the field on it's way to a tp on the other side?
No, it doesn't stop the pearl from passing through. It just stops you from teleporting into a 5 block radius around the ward. By the same token, Endermen can teleport across warded areas, just not into it on their first try.