The changes to how Wands are currently slated to work for the 2019 season onwards is a significant departure from both the original "punch" design of the wands (pre-2018) and the unlimited stacking but one use per wand design of 2018. Unfortunately, I believe that this is a significant regression in the abilities of wands - not just from the amount of damage players were able to put out using Medallion of Mystic Mouth in 2018 without the cost of consumables, but also from the pre-"infinite use" design that existed in 2017 and before.
To illustrate this, I've laid out a few scenarios of a Wizard entering a combat room and wanting to use a wand every round (be it because that wizard is out of spells, they have a Medallion of Mystic Mouth and wish to use their Free Action on it, etc.). I'll be looking at the token commitment for each scenario for each of the wand designs, and discussing the deltas between each one.
(Before we start, I'm aware that there weren't multiple damage types for the 2018 wands. Consider this a "had the 2018 design continued" analysis on that part.)
Scenarios:
1) Wizard comes in, uses 3 rounds of a Rare wand (3 punches in pre-2018 wands)
2) Wizard comes in, uses 1 round of a wand, finds out its the wrong type, uses a second wand for 2 rounds
3) Wizard comes in, uses 1 round of a wand, team slides crits and only one round is needed
4) Wizard comes in, uses 1 round of a wand, finds out the monster is immune to all its available wands, so stops using them.
5) Wizard comes in, uses 5 rounds of wands on the final boss of the dungeon.
Scenario 1) Wizard comes in, uses 3 rounds of a Rare wand (3 punches in pre-2018 wands)
Pre-2018: Wizard uses 3 total punches - the equivalent of one rare wand. That token is lost.
2018: Wizard uses 3 wands for 3 rounds of combat. No tokens are lost, but the wizard had to own 3 wands.
2019: Wizard uses 1 rare wand. That wand is lost.
Analysis: The Pre-2018 and 2019 scenarios are mostly identical. A clever wizard could use all but the last punch on multiple wands, in order to keep them around to turn into trade goods, but in the simplest scenario the two consumable paths are nearly identical. The 2018 wizard, with his permanent wands, needed to own 3 of them to keep up, but did not lose any tokens at the end of combat.
Scenario 2) Wizard comes in, uses 1 round of a wand, finds out its the wrong type, uses a second wand for 2 rounds
Pre-2018: Wizard uses 3 total punches - the equivalent of one rare wand, but split between two tokens. Depending on punches that were on the wand before, 0-2 tokens would be lost.
2018: Wizard uses 3 wands for 3 rounds of combat. No tokens are lost, but the wizard had to own 3 wands.
2019: Wizard uses 2 rare wands. Those wands are lost.
Analysis: Here we show that an unfortunate choice of first wand means that our 2019 wizard winds up using two rare wands. The pre-2018 Wizard would again have used the equivalent of one rare wand in punches for that combat. Our 2018 Wizard still needs 3 total wands for this combat. Our 2019 wizard is the big loser here: to wand in every round, the wizard must turn in two tokens.
Scenario 3) Wizard comes in, uses 1 round of a wand, team slides crits and only one round is needed
Pre-2018: Wizard uses only 1 punch from a wand. That wand is kept.
2018: Wizard uses 1 wand for 1 round of combat. That wand is kept.
2019: Wizard uses 1 rare wand. That wand is lost.
Analysis: Again, the 2019 consumable wand wizard comes out behind. The pre-2018 wizard used the equivalent of 1/3 of a consumable: under the proposed changes, our 2019 wizard only gets one use out of their wand due to the skill of the rest of the team.
Scenario 4) Wizard comes in, uses 1 round of a wand, finds out the monster is immune to all its available wands, so stops using them.
Pre-2018: Wizard uses only 1 punch from a wand. That wand is kept.
2018: Wizard uses 1 wand for 1 round of combat. That wand is kept.
2019: Wizard uses 1 rare wand. That wand is lost.
Analysis: Scenario 4 is functionally equivalent to scenario 3 in regards to resource consumption for the Wizard. However, it is a bad feeling to turn in a consumable and be told that it has zero effect (like what would have happened this year in the Ogre Mage fight had we been playing under the current ruleset).
Scenario 5) Wizard comes in, uses 5 rounds of wands on the final boss of the dungeon.
Pre-2018: Wizard uses 5 total punches: 1 2/3 rare wands worth of punches. Those tokens are lost.
2018: Wizard uses 5 wands for 5 rounds of combat. No tokens are lost, but the wizard had to own 5 wands to do this.
2019: Wizard uses 1 rare wand. That wand is lost.
Analysis: It is only in longer combats, without any need to change damage type on a wand (or move from multi-target to single target, etc), that the 2019 Wizard pulls ahead of their pre-2018 counterpart. The "infinite use" 2018 wizard has to carry around a lot more wands to make their scenario work, but also doesn't have to turn them in post-combat.
Final analysis:
The proposed changes to wand mechanics for the 2019 season are not only a nerf from the infinite use of the 2018 season, but also in many common scenarios a nerf to the old functionality of the punched wands as well. While reusable wands may have increased Wizard damage output significantly at the cost of only a neck slot (and having to carry a bag of wands for every room), the proposed wand change is far too harsh of a nerf. If wands weren't a significant issue pre-2018, then this change is far too strong. If they were, this still creates a potentially bad play experience for any wizard that wants to use wands, due to them being one-use-only instead of spreadable across multiple combats (if you used the wrong type, or had a short room, or had any other reason to not use a wand for the old 3-tick duration).