I feel like I started something.
If I might interject, T1 also requires a single attack per turn, something I found on a form of guide. However, every site I have visited does not pertain to this principle, as it does have a slight flaw. No ability to combine strikes, and it is hard to categorize some spells as a single strike: some could be multiple, others could not count. So the real matter is what amount of time do you use.
What I generally see is one person making a series of smooth motions, ranging up to multiple strikes or none at all. They usually stick to three or four total movements per adversary (in the cases of handicapped matches) and then wait to receive adequate information to respond and continue their strikes.
As for magic, I've seen many different types, in many forms. Some don't even fit in these standards set out. I dealt with a runologist once. Yes, he had cast runes that took time to prepare and had greater effect the more time he spent, but he also had an equipment type in his inventory which were pre-prepared and set in number, usually which were of his stronger cast variants. What this illustrates is that equipment, though unintentionally, is a bypass for any restraints calling for preparation to reach higher power levels. But it isn't like, in this example, he did anything wrong. He simply wrote it beforehand, and just needed one mark to make it work. But from the standpoint of his adversary, requiring charges to reach equal level spells would seem a disadvantage, seeing as he can access greater power with lesser effort due to inventory.
This is why I am of the personal opinion that such a setup as this Arena simply cannot be strictly regulated by a series of rules. Each ability must be taken with a grain of salt, and set in appropriation to their abilities.
A suggestion I might have is to not implement strict rules on how to spellcast, but instead providing guides as to how one can apply their spells. For example, what level of preparation would be needed for said spells based on potency, how much charge is required, etc.
I also propose that, perhaps, prepped spells should probably have more umph, simply due to nature. A character is allocating time to cast that spell. Charged spells could have similar potential, but also would generally be scaled slightly over, unless an overcharge was performed. Prepared spells can easily be said to lose potency, and so would rank other the others.
This is just a general concept I wished to put forth. Though I may have stepped out of line.