I absolutely love the touch mine, it'd be great for multiplayer servers based on competition and mild pvp and such.
Actually, the igniter block is cool as well, if a little overpowered (think fire barrier being the same switch as closing the door from the inside and such). I'd support it as long as it needed replenishing of the flint and steel, and maybe netherrack required to make it be able to burn forever without going out.
Not entirely sure about twigs and girders, they might be slightly too much of a shortcut for other traps.
EDIT: please, nothing with explosions. The point of TNT is that it's a way to make things explode but is fairly hard to get. No shortcuts there, PLEASE.
for the fire there is a plugin false book that lets u turn fire on netherack on and off just like his thing and a lot of bigger servers that are very popular have it.
i came to this and i was like 'yeah i finnaly found a block like the igniter block! now i can roast griefers alive!! it looked like a mod and when i reached the bottom i could not find the link and was really disappointed. i would really love a block like the igniter block and have been searching for it for a long time. please could you make the block.
thanks, :Flint and Steel:
All these things can be done in the game in one form or another, particularly using piston doors. The only thing that is still valid anymore is the 1 way glass which just so happens to be in the scrapped idea section of the thread.