To answer indirectly, I'm going to start off with stating that the wording in 5e can be ambiguous.
Here are a few others that I personally came across where ambiguous wording caused issues:
In the case of Wish, this is also ambiguous, as the "requirements" of a spell are not explicitly explained. You can end up arguing about the semantics of a spell until the cows come home. However, Jeremy Crawford has explained the function of Wish with a Tweet:
Wish spell: (1) Duplicated a spell of 8th level or lower? No stress. (2) Did anything else with wish? Stress. #DnD
The "stress" mechanic used here identifies the difference. Wish states that if using the spell to duplicate a spell of 8th level or lower (emphasis mine):
You don't need to meet any requirements in that spell, including costly components. The spell simply takes effect.
This means that by simply speaking, you cast the spell. You don't need the components, or spend the time to cast the spell, the effects of the spell just happen, with no extra effort. Referring back to Jeremy's tweet, this would not induce any stress.
If, however you wanted to cast the spell that functions outside the bounds of the spell's ability, that does incur stress.
Let's use "Tsunami" as an example:
Casting Time: 1 minute
Duration: Concentration, up to 6 rounds
A wall of water springs into existence at a point you choose within range. You can make the wall up to 300 feet long, 300 feet high, and 50 feet thick. The wall lasts for the duration.
Wish states that I can make Tsunami appear in the same action that I cast the spell, rather than spending a full minute chanting and gesticulating (V & S components), anywhere that I can see, and that's the spell done. I have cast the spell, by using Wish. If I wanted to, I could then cast Tsunami again elsewhere, the very next turn (if I had the spell in my list).
If you think about it, that is already an incredibly powerful ability. If you used Wish to summon a wall of water that big, instantaneously, that lasted for 36 seconds (6 rounds). That's 4500 cubic metres of water just appearing, and then staying in place for 36 seconds, before dissipating. To be able to maintain that without spending the time to concentrate on holding the water in place, and then spending the next minute (10 rounds if you're in combat), recreating those same effects would definitely be beyond your normal ability. You could flood an entire city in just over a minute.
So, in conclusion: Wish can be used to instantly cast any spell without the need of components or a casting time, without any further effects. If you wish to bypass the concentration, alter the range, or even the size of the spell, that is outside of the standard rules, which will incur stress. So by that logic, the only "requirements" of casting a spell are the Components, and the Casting time.