Originally Posted by Dexai
Originally Posted by Niara
Originally Posted by Drath Malorn
I'm less convinced about the power/balance issue.

The power issue comes up in a slightly more nuanced way than the' team has an optimal play that they then will always use' boring combat problem. Most commonly the abuses and breaks that arise from being able to move yourself in the initiative order are to do with spell and ability timing, and getting more value for them than intended. Here's an example:

I'm a monk, and there's a big bad in front of me. The turn order goes: Monk, BBEG, Fighter, Barb, Wizard.

I hit the Big bad and stun him. Huzzah. He's now stunned until the *end of my next turn*, giving everyone one round to wail on him, and have advantage on things or to have him auto-fail some types of saves.
Everyone else takes their turns, and then it's me again; "I delay my turn until after Wizard!" Now everyone gets a SECOND full round of that stun, and the BBEG can't do anything about it, and has to skip a *second* turn, because it still hasn't been the end of my next turn because I ducked to delay until after him. And it's cost zero extra resources.

There are other examples as well, but most of them are to do with the timing and duration of spells and class abilities that are balanced around being active for a specific amount of time, metered by the initiative order. Begin able to change it at will, round to round, does a lot more than people realise at first glance.

You can only delay your on your turn, so the effect will already have ended when you delay it :P
It realy depend on implementation.
You can put decision to delay befor the "start" of your turn.
You can make it so your turn isn't "ending" when you delay it.
Or any other way.

Dungeon master guide contains a variant rule to reroll initiative every round. Haven't had experience using that rule, because it increase bookkeeping. Though in that case randomness will probably balance this problem more in favor of monsters (just cause there are much more of them than players).