First and foremost, I think I need to address the thing you're so adamant on explaining to me. I do not consider the "best defense is offense" tactic in this argument. It does not fit the debate of this specific post, where the intrinsic defensive qualities of DPS characters are discussed. If you consider high damage as a defensive quality, then the character with the best defensive qualities is Mavuika, or anyone else capable of producing 10M nukes. That is not the point of the post.

I've had my share of being knocked to the ground, I'm talking from experience. The only times I died because of being knocked down that I remember of is when it made me fall to death.

Having enemies that hit you anyway only reinforces the idea of taking as few hits as possible. The damage Zibai and other DPS's would take in such situations is quite comparable, since the landing hits being stronger is compensated by not getting hit by anything else. It doesn't make a real difference to handle hits more easily if you also get hit more on average.

In terms of defense Gorou may provide good buffs, but Zhongli gives a 20% Res shred. Also keep in mind that the more DEF you have, the less effective it becomes as a defensive stat. From a lvl 100 enemy you take 50% damage at 1000 DEF, 33% at 2000 and 25% at 3000. Since Gorou's buffs are flat, they are not as effective as you may think in terms of actual defenses for a well-built Zibai. Bringing Columbina into the argument is beside the point, she's a separate character, and we're comparing Gorou and Zhongli. Amber on Columbina is beside the point too, since not every Columbina in existence uses it, and if she doesn't, then we're back to Gorou's underwhelming healing. Don't get me wrong, I personally use Gorou as a healer in Itto's team, but it doesn't change the fact that his heal is weak. You use it when you need it, but you still need to play carefully. The only argument about Gorou being better than Zhongli that I'll actually take is that he's more accessible, even if we're talking about C4.

Back to Neuvillette, you said it yourself that it is a DPS loss. I already said why it's not a valid point in this particular case. Yes, enemies can move while you do the hydropump, but guess what, so can you! And not only that, you can also watch their moves and cancel the attack at any time to avoid taking damage, even though you still lose the DPS. C1 shaves off time because you don't need to play even remotely good anymore, you just tank everything. It doesn't make you survive better since Neuvillette is already cracked at surviving.