I agree with this. Though repetitive, Scatter spam was fine. Considering they went for actions replaced by other actions in the same hotbar slot depending on resources/effects, they could have gone with Scatter => Impact as you mentioned.
Additionally, they've set the precedent of Tier II Verspells being AoE, which means if they follow that to its logical conclusion AoE gameplay will likely turn needlessly complicated once Verfire II and Verstone II enter the picture.
I opted to commit the cardinal sin of clicking with the mouse cursor on the AoE skills. I'm not bending my wrist in a weird direction just to cast AoE. What could have comfortably fit on CTRL-4 (CTRL-5 if I stretch) if it had been one button is now on the other side of the hotbars.Though, more to the point, there's also extra shelf space being taken and I'm not fond of the contorsions required on the keyboard to simply cast the things (It was one thing to mash Ctrl+0 in Stormblood, but now I have to dance between Ctrl-2, Ctrl-3 and Ctrl-4 a whole lot and my left hand really resents going through those contorsions).
I agree Acceleration at most needed 2 stacks (for those instances where you procced nothing but Acceleration is still on cooldown). If I were to hazard a guess, Acceleration will likely be bumped up to 60s or 90s cooldown per charge.