No lost GCD's, but I think a "spell not ready yet" message does appear. Also, if it is on CD, then the next spell won't cast if you pressed it while casting Wrath, but that happens with or without the Starsurge.
As I understand, you get attack queues now that works somehow together with latency. If you use an ability, and use another one before the first is finished casting or the GCD is over, the next ability is queued. When you finish the cast/GCD, the next ability is used. It does mean that you can't spam keys while on GCD's. I've had cases with a Feral where I changed my attack and had spammed the previous one a bit. I would still use the last, spammed attack before changing to the new attack.
In the Wrath/Starsurge macro, I think what happens is that while Wrath is being cast, pressing the macro again causes the Starsurge to be queued. If the Wrath finishes and Starsurge is off CD, then that is cast next. On CD causes an "not ready yet" message or similar. If you don't press the macro while Wrath is still being casted, but wait until it's finished, then Starsurge never gets queued because it's on a separate /cast command.
As I understand, you get attack queues now that works somehow together with latency. If you use an ability, and use another one before the first is finished casting or the GCD is over, the next ability is queued. When you finish the cast/GCD, the next ability is used. It does mean that you can't spam keys while on GCD's. I've had cases with a Feral where I changed my attack and had spammed the previous one a bit. I would still use the last, spammed attack before changing to the new attack.
In the Wrath/Starsurge macro, I think what happens is that while Wrath is being cast, pressing the macro again causes the Starsurge to be queued. If the Wrath finishes and Starsurge is off CD, then that is cast next. On CD causes an "not ready yet" message or similar. If you don't press the macro while Wrath is still being casted, but wait until it's finished, then Starsurge never gets queued because it's on a separate /cast command.