um not sure where i said you shouldn't use the ogcds on cd. in fact my arguement to not being in melee range is because there is no benefit to doing it, all this does is set you up to have to move because of an AoE. being max melee is definitely fine and is the best place.
"don't stay in melee range but don't stay far in the corner as you miss heals and buffs. it's not a terrible idea to use corp a corp after displacement since you don't always need it to start a melee combo."
That is what i said.
Using CaC after displacement allows you to regroup with the party for heals especially in heal intensive figths like o8s. Also you don't have to use your movement tools immediately as they come off cd, this is because manafication refreshing the timer already alters the time that you'll get these abilites off cd. the golden rule is to use them on cd if you don't need them for a mechanic.
Displacement has a significantly longer animation lock than any other oGCD and CANNOT be double weaved with any other oGCD without clipping your GCD. It also CANNOT be single weaved after Enchanted Riposte and Enchanted Zwerchhau (even if your back is against a wall and you stay in melee range, you will still clip) but it CAN be single weaved after Enchanted Redoublement. Assuming 100% uptime, when you use Manafication optimally you will actually have approximately 5 seconds left on Displacement and 10 seconds left on Corps-a-corps. Since Manafication resets the CD for these two abilities this means that you can hold both for up to 30s each per Manafication use in order to use them to deal with mechanics and not lose a use. This is convenient as there are times where we do not want to use Displacement on cooldown since it will cause us to move out of heal range during a heavy AoE damage part of the fight. We can safely wait until after the healing is done to use Displacement and not have to worry about missing a use of it. This also places them in the bottom of your priority list for oGCD usage.
Source: https://www.mooglemedia.com/rdm-guide/#ogcd