It slows you down. It definitely slows you down, and this has nothing to do with the limitations of integer waits (because integer waits are obviously a drop in efficiency, so we don't need to argue about them).
Expect to lose at least 0.2 seconds per macro execution, which can easily cost you 2~3 GCDs each minute if you macro enough abilities. In an eight minute fight, that's 16~24 GCDs lost (that's almost a whole minute's worth of actions)!
Besides that, your macro is misordered. What you wrote will do the following:Dragonfire Dive will execute as a gap closer or an oGCD. If you press this when weaponskills are okay, Chaos Thrust has priority, which means it'll break your combo if press the button at the wrong time. When misusing macros for combat actions, you typically should put the GCD ability at the bottom.
- Use Blood for Blood on cooldown.
- Use Chaos Thrust if distance <= 3 and TP >= 60
- Use Dragonfire Dive if distance > 3 or TP < 60 or oGCD
- Use Haymaker if (recently dodged or TP < 60) and TP >= 40
- Use Mercy Stroke if not recently dodged or TP < 40
You'll almost never execute Haymaker or Mercy Stroke. You can improve this drastically by just never using Haymaker, because its potency is far below the mean potency per GCD of the DRG rotation. Mercy Stroke is also so restrictive that it should be placed higher up or the stars will never align such that it executes.