How would the game break if one used a "single initiative" system?

[JohnPaulB]

Originally Posted by n00b

Complete n00b trying to teach myself Melee here.

I was wondering the reasoning behind the double initiative system: Both sides move based on the initiative roll, and then individuals act based on Dex order.

HOW would the game break if one used a "single initiative" system instead? That is, one in which combatants move and immediately act. For the sake of discussion, the order could be

a) Determined by a die roll (side initiative),
b) Determined by Dex (individual initiative), or
c) A combination of the two, such as 1d6+DEX.

I am asking HOW the game would break rather than WHETHER it would break because I presume that there has to be a deep reason why it works the way it does. But having read the rules and tried a bit of arena self-play, I cannot see any obvious reason!

(Edit: Notice I am asking about basic Melee rather than Melee+Wizard or full-blown TFT. Answers about the full system are welcome, but I'd like to understand how Melee works on its own first.)

In the late 70s when I learned TFT, I must have missed the part about "then fight in DX order." Or I probably forgot that part.
Anyway, what our players ended up doing was:

1. Group Initiative: Roll d6 to see which side chooses to move first.
2. Movement of both sides, all of one side, then all of the other as determined from above.
3. Magic and Missile Weapons go next. Determine that order by adjDX. (We did this first as it got rid of any non-adjacent hex actions.)
4. Then using Igo/Ugo, the player who won the initiative roll chooses one of his characters (not a magic or missile character) and does his action.
5. Then the other player chooses one of his characters and does his action.
6. This back and forth continues until all characters have done their stuff.

We played TFT where others weren't allowed to see your stats. You could tell members of your party what the stats were, but the enemy didn't know.

The enemy could make a guess as to what your ST was by how heavy was your weapon.
But they didn't know your DX or adjDX. They could assume that since you had a medium shield, you were at least -2DX, but not what your DX started at.

They (your opponent) only found out when you rolled your DX.

This proved to be another tactical consideration because if you had a high DX and ST character and you selected a lower ST weapon and no armor, you could surprise your opponent, who might have underestimated your character. Of course, once this surprise was used, the next time that character came up, his adjDX was known.

I had since relearned the rules.