Theres not enough macro space to play Ninja.

[Adamantium]

But I still don't see how its a DPS loss, its not about remember mp its about saving space and time, if I can get the same effect from 2 spells on one button than 2 separate buttons when I'm limited on space I'd rather do that. All it does is queue up the one it has the ability to do.

Because the choice between using Thunder 1 and Thunder 2 is dependent on whether you go for 251 Piety or not. If below 251 Piety, use Thunder 1. If at 251, use Thunder 2. There's never a need to have both Thunder 1 and Thunder 2 available to you. Combine that with the skill queueing issue that macros cause, and it's a DPS loss simply because you cast it a fraction of a second later.

Really only matters to people who like to min/max. Not a big enough deal otherwise, but it's still, objectively, a DPS loss.