I’m not sure if anyone else has noticed, but it looks like there is a slight DPS loss even when it doesn’t drop inputs (such as when using macros which don’t work with it). I tested this out by sitting at a target dummy and casting just wrath. I used a damage meter to isolate just wrath damage and DPS for wrath was 1626 for press and hold casting but was able to get 1801 DPS by casting wrath normally (ignoring crits).
Another thing I looked at was how many casts I could complete in a fixed amount of time. Press and hold casting had 73 casts in 90s while normal casting had 80 casts in 90s. According to my tooltip, wrath has a 1.1s cast time (32.5% haste) so the normal casting is very close to what the tooltip says yet press and hold casting has a 1.23s cast time! (According to my math 1.5s base divided by 1.325 is 1.13s). Changing spell queue values (even down to 0) did not seem to have any impact for press and hold casting.
Using the cast time and haste math, press and hold casting means going from 32.5% haste to effectively 22.0% haste!
Can anyone else confirm this result? To do so, make sure to only look at the DPS from one spammable spell and ignore any passive damage like trinkets if possible as well as crits. When I watched it as I was casting, it looked like the error range wasn’t even close. The strategies varied by about 150 DPS consistently over time.