Yes your summary of the next wave button is correct. Currently the only use of it (besides saving time) is with the impatience's wrath set bonus.
Actually my goal with the game (especially early-mid game) is to make it so entertaining that a speedup is actually not needed. That's why I set the item level of the scepter quite high, so that it drops end of mid-game to start of end-game.
I'm not that sure if it is needed anymore, now that the amount of waves is fixed to 200.
But I might be wrong here and a speedup is quite welcome after some time.
What about a player skill, which grants you the scepter of time when you start a game?
Cause letting the player choose item to take to the next game would be quite hard to balance out. Consider taking some of those very strong uniques :-)
Anyways, I will keep this in mind for one of the next polls on the site!
Cheers!
I really like the idea of having the sceptre in the beginning because I actually like seeing real time mid/end game especially with the wrath set because I find it too easy to miss the timing between shots with the wrath set.