Wish lets you ignore the requirements of:
- providing components
- providing the correct time casting
- providing an appropriate spell slot
- having that spell to be on your prepared or known spells list
- having that spell be of an appropriate level or school
Requirements, unfortunately, is never really given a game term definition.
So as with all words that don't have a game term definition, we should attempt to use the standard english definition.
Using that, we can say that anything is a requirement if it prevents you from casting the spell.
So with that in mind, here's the justification:
[Level] [School] - If a spell is not normally of the right level or school for you, you cannot cast it. This is a "requirement".
Casting Time: x - If you do not spend the amount of time specified, you cannot cast it. This is a "requirement".
Range: x Having nothing in range does not actually prevent you from casting a spell (for example, readying) - it prevents you from targeting it. This is NOT a "requirement".
Components: x, y, z (special) - if you cannot provide the proper components, you cannot cast the spell. This is a "requirement".
Duration: x - duration has nothing to do with whether you're capable of casting a spell. This is NOT a "requirement".
Concentration - When casting a spell normally, you can choose not to maintain concentration. The spell will end, but you are not prevented from casting it. This is NOT a "requirement".
Classes: x - If a spell is not on your prepared or known spells, you cannot cast it. This is a "requirement".
Description: [Effects] - Effects can only take place after casting is completed. This is NOT a "requirement".
Spell Slot - If you cannot provide the right spell slot, you cannot cast a spell. This is a "requirement".
Specific features (in addition to Wish) can negate some or all of these requirements, or even add requirements: see Subtle Spell or Ritual Casting