Thespian's Stage question

That doesn't work.  Once you copy another land it loses all abilities of the first land you copied and gains the new ones. 

You can't make it a kessig wolfrun + nephalia drownyard + maze end.

706.2. When copying an object, the copy acquires the copiable values of the original object’s characteristics and, for an object on the stack, choices made when casting or activating it (mode, targets, the value of X, whether it was kicked, how it will affect multiple targets, and so on). The “copiable values” are the values derived from the text printed on the object (that text being name, mana cost, color indicator, card type, subtype, supertype, expansion symbol, rules text, power, toughness, and/or loyalty), as modified by other copy effects, by “as . . . enters the battlefield” and “as . . . is turned face up” abilities that set characteristics, and by abilities that caused the object to be face down. Other effects (including type-changing and text-changing effects), status, and counters are not copied.

Although there is a rather comical combo in legacy that pairs Thespian's Stage with Dark Depths as the copy won't have any counters on it...

Well with the current legendary rule if you copy the land you destroy both of them.

After M14 is released you can choose which one to sac so it'll work then.

Thanks for the heads up on that combo!
I currently run Dark Depths in a RUG EDH deck simply because I can often power through the counters in just a couple turns, but looks like I better pick up a copy of the stage before word gets out!