I wanted to help you folks out, I read a few people saying that they are having some ability delays, and I feel ya, but what you think is ability delay is not delay at all.
ESO unlike just about every MMO has it set up were abilities go off upon key release instead of key press, having abilities go off on key release does just as it sounds so any delay on your part when pressing a ability will seem delayed.
I found a simple fix using a programmable Razer Naga Mouse, go into your software macro command (Synapse 2.0) and recreate the ability keys to go off on key press by creating a macro that reads (example: 1 down-1 up and so on) with no delay input and bind it to your keyboard or mouse buttons to play on key press, this will make all your abilities that you macro go off the moment you press the key, this made such a major difference in my game play I am shocked that ESO did not input this as a default function into the game.
Using the program Razer Synapse 2.0, I will do my best to show you what I did to program my mouse side buttons to trigger my abilities to go off on key press.
Step 1: Open up your macro tab.
Step 2: Click the + symbol on the left hand side below were it says "MACRO" . now name your macro under "MACRO NAME", (I named the macros in this case ESO 1-6) in this picture you see ESO 2 (meaning the number 2 ability key).
Step 3: On the left hand side click the "NO DELAY" so that it is enabled.
Step 4: On the left hand side click the "RECORD" then press the key of choice once.
Step 5: Click stop "RECORD".
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Now that you recorded the keys you want to use in game you will have to set them up, below I am going to bind my macro to my mouse side buttons, click on the number keys that you want to use.
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When you click the button that you want to use you will see a drop down tab, select "MACRO" under "BUTTON ASSIGNMENT", then below that you will see "ASSIGN MACRO", open the drop down tab and find the macro you created in this case ESO 2.
Below that you will see "PLAYBACK OPTION", select "PLAY ONCE".
Now just repeat the process on all the keys you want to macro and you are done.
Open ESO running the program in the back round and enjoy.