It's also slightly slower to select abilities from other than the active hotbar using a controller since you have to press two button combinations (first to switch hotbars, then to select the ability) compared to a keyboard with enough buttons to bind two or three hotbars worth of shortcuts. This can somewhat be mitigated by arranging abilities in logical sets. For instance on DPS and tank classes I typically have single target and AoE hotbars, on healers I have a damage-oriented hotbar and pure heals hotbar. Selecting targets also takes a few more button presses on controller compared to keyboard. I can raid with either, but I feel that on keyboard I can react to unexpected situations a little bit faster.