I'm pretty darn excited about the easy teleportation ability. I'd gotten into the habit of making giant networks of railway carts all over the place at great personal expense of wood, iron, and
time. Eventually, actual teleporters would be placed down in tiny boxes shielded from enemies except for a small platform in the bottom one could drop through, scattered every four hundred blocks or so east or west, up or down. They weren't that hard to wire thanks to the Grand Design. Now these Pylons will ramp things up quite a bit in the early game and possibly make all of that unnecessary.
I've honestly never really built any kind of town that deep underground. The most I've ever done is have a Dryad move into an underground mushroom biome so she could sell me mushroom seeds. ... ... ironically to help make another mushroom biome above ground for the Truffle. I like making giant self-contained square boxes for the Truffle and Witch Doctor (Separate, of course.) so they can sell their unique stuff.
I wonder if any other NPCs besides the Truffle will prefer the magic mushroom biome. ... ... Maybe the Party Girl.
Heheheheh.
But you didn't hear it from me.
--------------
I actually wonder how this will affect adventure maps. I'll bet many of them will have to be replanned. Imagine if you bring up an old-style adventure map into 1.4, and their surface houses just HAPPEN to be in the right geographical configuration to let you get a Pylon, so you place a Pylon and gain access to free teleportation. Fascinating.