You could, mid-combat get a full night's rest; being completely healed and getting all your spells back, for instance, or cast Stoneskin on the entire party.
Umm...that is horrible and not how the spell works at all...that is the worst interpretation of the spell ever. Wish is an extremely punishing spell to cast and would leave you extremely weakened for several days.
Here is how you're left after casting wish: "The stress of casting this spell to produce any effect other than duplicating another spell weakens you. After enduring that stress, each time you cast a spell until you finish a long rest, you take 1d10 necrotic damage per level of that spell. This damage can't be reduced or prevented in any way. In addition, your Strength drops to 3, if it isn't 3 or lower already, for 2d4 days. For each of those days that you spend resting and doing nothing more than light activity, your remaining recovery time decreases by 2 days. Finally, there is a 33 percent chance that you are unable to cast wish ever again if you suffer this stress."
