Exactly, it's like Improved Initiative in D&D. It's great on the first round but after that it's cyclical and doesn't provide any real advantage.
Makes a difference for evocation blocks unless you run them like D&D. You can divert energy from a evo-block only if it hasn't been used in the current exchange. Like 2nd edition, a round/exchange is a discrete, absolute object, and you don't base it off whatever character you are focused on at the moment.
Actually, the artificial exchange rules apply to delaying too:
You may opt to delay your action until a future point in the exchange, allowing you to interrupt someone else’s action later in the initiative order. Once this happens, your initiative is set at that point for the rest of the conflict, unless you delay again.
Consider the Harry, Mouse, Ghoul example.
1. Mouse
2. Ghouls
3. Harry
Mouse can delay to interrupt the ghouls OR Harry. If he interrupts Harry, then the initiative order is like this:
1. Ghouls
2. Mouse
3. Harry
At this point, Mouse CANNOT interrupt the ghouls in this combat anymore since he goes after they do each exchange. It isn't possible to delay until the next exchange.
Good point with the system as written: Super-fast guys can't be interrupted. If something has mythic speed, Mr. Slowpants can't interrupt their action. That's realistic.
Bad point: If Mythic Speedman delays to interrupt someone, say Mr. SuperSlowPants, then Mr. Slowpants can now interrupt Mythic Speedman in the future. That's not realistic.
Bad point2: Not necessarily a lot of fun if you can't potentially interrupt the superfast guy, though perhaps an invoke for effect should be the way to handle that. Also, it makes some things regarding the initiative order, spell duration, and the like seem rather arbitrary. If you go first in a conflict and cast a spell that last X exchanges, it essentially lasts longer than if you go last and do the same spell. There's a similar problem with diverting spell energy from a block...it's just weird.