It's not even a significant, tangible problem for most players, if it feels bloated to use AD/C&S in an opener then don't use them both, just use C&S for that quickie oGCD damage and tiny bit of mana gain after blowing an Edge/Flood/TBN and save Abyssal Drain for little later when you need some healing on a mob pack.
It's an easy player choice anyway, not like Abyssal Drain was good for anything other than Heals on 3+ Mob packs. I don't know the mana value restored yet but I hope it's more than a mere 600 mana. Besides, both are oGCD skills, not like they are going to ruin combos or rotations.
This change reminds me of someone reaching for a few pennies when there are stacks of $100, $20 bills offered right there if Issues were like money on the table. Of all the things that can be picked up and handled, they went for the pennies. This is Comedy Gold too but still, at the end of the day a lot more could've been done to make player base happy besides providing Comedy & Meme material.