CRUSHERS AND WORLD PORTALS!!!
I have found some very interesting things in the Puzzle Maker file system
In the common/portal2_dlc2/materials/puzzlemaker folder we can see some very interesting things. 1 is the textures for the much wanted signs, like the 1, 2 and 3 signs represented by dots you see in Valve's levels. There are also others like the moon sign and wave sign.
Then if you precede into the palatte subfolder, we can see....
CRUSHERS!!!
Also, world portals!!!! And a slightly odd 3 faith plate thing....
So I'd say Valve were working on these, and then didn't end up implementing them in time. Do you reckon we will see them sometime soon?
Evidence
http://gyazo.com/facc2391299bc768ec2c9723d2c5f65e
http://gyazo.com/88db55f017ea501bfb0bd61615d4caab
On another note, does anyone know how to implement new instances/textures, like the broken glass, dirty walls etc. into the game properly? I've seen people attempt it, but does anyone know how to actually do it?
Load your map in Hammer, and change the textures?
I don't use hammer, mainly cause it just seems clunky and hard to pick up compared to the level editor. I want to have at least some of the capability of hammer, but with the convenience of the level editor
they won't be worked on and they wont be added.
Crushers , autoportals, and 128 catapults uses special things that Valve doesn't want to add.
Crushers , autoportals, and 128 catapults uses special things that Valve doesn't want to add.
What do you mean special things
and why are they called 128 catapults
Perhaps 128x128 width x length (or 3 in one)
The 128x128 catapult is indeed the triple faith plate, I think they're scrapped from the PTI.
The crushers are not in the PTI for two reasons:
1) You need invisible triggers for them. (valve doesn't want invisible stuff in the pti.)
2) Almost every crusher in game is different, so one instance won't cover it all 
Maybe the crushers will be added later 
but I think this shows that they at least initially started invisible triggers, so they did consider it
but I think this shows that they at least initially started invisible triggers, so they did consider it
They did, and they still consider it for a possible future update. 
It is hard to pick up compared to the level editor. But you can really just build everything you can in the level editor and then add and delete what you can't with the PTI by using Hammer.
This way, you won't have to go through countless tutorials for now. Just watch one that describes the basic ways to look around and select things etc., and then search for tutorials about the one thing you want to implement and do it.