Personally, I would hold off on sawing off and releasing each of the tentacles/chains/whatever too quickly. Kill them as they are released to avoid having it become too unmanageable. If they revive, focus on them. I've played many online matches with Japanese players that have gotten the hang of things and we always take them down as quickly as we can. The boss becomes a pushover once you do that. His other attacks are easily avoidable. Remember to thorn your way out of the vacuum/suction.
Thing is, that doesn't work well with the gear one probably has at CODE 7 during story and with AI companions lol. That just results in "Oh god there are 8 chains, all the AI keeps dying to lightning bursts and I can't even stand up".
The longer, less efficient method ensures you won't get swarmed by a billion at once and keep things more manageable for that initial clear.
When you have good gear and/or competent people, it's another story though.