Overall I love the thoughtfulness of your post. Just a great overview of the potentialities and consequences and ways to approach this, so applause for that.
I do find the section above a BIT dispiriting and sad. Absolutely it's a challenge, but I do think that with a table of friends willing to give each other reasonable benefit of the doubt, you can find a better outcome than the three bad ones you outline.
As a DM I lean toward letting Wish do truly awesome things, but not being a "win the campaign" button. And I think if I talk to my players about that rationale they will generally understand and be on board with that.
I just have a pretty dim view of mechanics
specifically designed around creating and fostering, rather than removing or at least mitigating, DM-player "arms race" types of behavior. I find that
wish in specific is an extremely potent locus of such things: players dream of the incredible, world-altering power, and DMs have been specifically encouraged to approach it in a very antagonistic way.
Like, here's the 5.5e text for the relevant use of the spell (underline added for emphasis; bold in original):
Reshape Reality. You may wish for something not included in any of the other effects. To do so, state your wish to the DM as precisely as possible. The DM has great latitude in ruling what occurs in such an instance; the greater the wish, the greater the likelihood that something goes wrong. This spell might simply fail, the effect you desire might be achieved only in part, or you might suffer an unforeseen consequence as a result of how you worded the wish. For example, wishing that a villain were dead might propel you forward in time to a period when that villain is no longer alive, effectively removing you from the game. Similarly, wishing for a Legendary magic item or an Artifact might instantly transport you to the presence of the item's current owner. If your wish is granted and its effects have consequences for a whole community, region, or world, you are likely to attract powerful foes. If your wish would affect a god, the god's divine servants might instantly intervene to prevent it or to encourage you to craft the wish in a particular way. If your wish would undo the multiverse itself, threaten the City of Sigil, or affect the Lady of Pain in any way, you see an image of her in your mind for a moment; she shakes her head, and your wish fails.
Notice some of the ways the text explicitly promotes a "monkey's paw" type of result. It specifically boosts
outright deleting a character from the game as an acceptable "wish went wrong" consequence. It also encourages some pretty openly unfair "interpretations" of what the player said. Wishing for a particular artifact simply
is not the same as wishing to be in that artifact's
presence. The whole point of the
wish spell is, ultimately, to be a monkey's paw kind of thing, a "phenomenal power always bites you in the butt" situation.
Now, if you and your players go into it seeing it as a negotiation and setting down your own rules and negotiation policies, that's perfectly fine. But, IMO, there are other and better ways to frame this, ways that don't explicitly encourage DMs to be punitive and that discourage players from considering inappropriate bargaining positions to begin with. As an example, a move I love from Dungeon World--one which I have taken away from the Wizard class alone and made accessible to anyone, even non-spellcasters, if they can justify why they'd be able to do it. (I haven't had a Wizard player in a long time, so if I did, I'd offer them recompense of some kind to make up for taking away one of the baseline class moves.)
Ritual
When you draw on a place of power to create a magical effect, tell the GM what you’re trying to achieve. Ritual effects are always possible, but the GM will give you one to four of the following conditions:
- It’s going to take days/weeks/months.
- First you must __________.
- You’ll need help from __________.
- It will require a lot of money
- The best you can do is a lesser version, unreliable and limited
- You and your allies will risk danger from __________.
- You’ll have to disenchant __________ to do it.
Notice here:
I as GM am not allowed to say an effect simply isn't possible at all. But, conversely, I am explicitly given the option of "well...you can't do ALL of that, but you can do part" or something similar. I could also pick a cost that the party might be unwilling to pay. This sets up a reasonable negotiation situation: the players want to pick something that won't be liable to cost them something they aren't willing to give up, while the GM (due to other GM-binding rules) must come to the table wanting to "fill the characters' lives with adventure", meaning, just shutting down ideas because they aren't your personal preference
is not an acceptable behavior. Both sides go into the negotiation having a good idea of the expectations, and those expectations are fair and, very notably,
do not push either party toward negative/disruptive choices.
I find that
wish is almost a study in how to NOT do a creativity-boosting option. It's so difficult to get to (since few campaigns reach level 17+), so players expect it to do great things....while DMs expect to keep a tight lid on it. It's written with explicit encouragement of decidedly anti-player, harmful-to-the-gameplay-experience consequences for DMs to inflict on impertinent players, all while giving players almost total freedom
other than the looming threat of experience-harming consequences if they aim too high.
It is good--excellent, even--that you have a group where everyone is already on board with finding a good, productive outcome. My problem is that the rules do very nearly everything they can to make that harder for both the DM and the players. I know this isn't exactly the most popular opinion right now, but I very much prefer rules that work consistently and that actively encourage the types of behavior the designers want to see, rather than both (a) encouraging behaviors that aren't great (like actively antagonistic DM behavior), and (b) focusing only on
punishing those behaviors you
don't want to see. I find many games are riddled with perverse incentives, and 5e, while not the worst example of this, has lots and lots of it, on both the player end and the DM end.
"When the moooooon is in the seventh house... I mean eighth house... I mean... 
