True indeed, but if you are a Wael Priest you have many speed self buff, litanies and prayers usually are fast, you have some fast debuffs and with Wael's spells defense plus BDD + SoT you have plenty of time to cast average and slow spells as Minor Avatar, DftF and so on
Arquebus is better but a dual wield pistol can do wonders as well. Even if mid-later game pistols are better, Eccea's Arcane Blaster especially
Keeping in topic I agree is better a Priest of Wael / Psion as combo (more defenses while building focus), if you wanna go more aggressive and use an ascendant, then I'd take Skaen to enhance focus through defense debuffs early (Barbs of Condemnation, Divine Mark) then you'll get Finshing Blows and Minor Avatar, as Spiritual Weapon you have club which helps Cipher's spell with its modal and you have also some defensive spells (Escape, Shadowing Beyond). I think he could be also pretty funny