2. Two things here. First, it depends on what you're killing. If you're just clearing packs of mobs, then yeah, DB has a slight edge. Not a huge one though, since physical builds get to supplement their IB dps with BB + Wind Cutter. If you're killing MVPs though (which, as a huge part of actual PVM you would be) obviously higher single target dps way outperforms mediocre AoE dps.
DB AOE DPS is not mediocre by any means to a well geared DB RK, which is a requirement for MvPing anyways. With stringer, the DPS can get into the insane range.
3. I don't even... Not only do you have Parry, but RKs have the highest base health pool in the entire game and along with Inc HP Rec 10 one of the highest potting efficiencies too. Even without a shield, damage that doesn't get mitigated by Parry can be pot through incredibly easily. The only MVPs where a shield really matters are the super high end ones that you wouldn't be able to kill solo without crazy gear anyway (e.g. Bio3/4 MVPs)
How is that superior to DB RK? Not only DB RK have options to use Parry, runes, a shield. DB RK can also be useful in the party while defeating high end MvP like Ifrit.
4. This is ridiculous. You're seriously saying you'd recommend a new player to go DB build and then say, "Oh, don't forget to triple client and level a Maestro+Wandy at the same time as well because that's just a part of the build"? Triple clienting is a valid strat yeah, but it's definitely not a part of the build and it gets out of hand when you start judging builds based on how many other classes you can alt. If someone told me I had to level 3 characters to play a certain build I'd tell them to off.
Same goes for the argument that I need to grind 2-3 B just to make a build viable, I'd tell them the same. DB RK by no means required string / wandy to perform well, but the benefits are just too great to not exploit.
5. DB RK is pretty close in power to physical RK solo, but is a lot better in parties. Yup. So how does this lead to the conclusion that physical RKs are worse in every way? Obviously seems to me like they're unique builds each with their own distinct strengths and weaknesses (this is the third time I've said this lol)
1 Build can excel in 2 scenario, where the other excels in only 1 scenario and fall flat on the other. It's logical to me that's DB would be superior in that sense.
6. You're right, DB RKs have a much higher damage potential. Reaching that potential is anything but easy though. Tao/Kiels are common on the server? Tell me more about how easy it is to get my own set, then. Do I try and outcomp MVP/godded players for the natural spawns? Or do I just keep greeding in TIs til I make my own 50b+? Pretty easy yeah?
I am not saying that Tao and Kiel are common, but it's not as rare as many people make it out to be. There are a lot of Tao and Kiel in circulation on the server due to how many years they have been farmed or in the summoners. It may take a year or two to earn 50B, but that's not something entirely impossible as you make it sound. From my experience, I have encounter far more many Tao/Kiel users than say 2x Meg physical RK.
7. Nor do they have to. The build relies on chaining several skills together for powerful AoE dps and frenzy/crit for even more powerful single target dps. Just because they don't benefit off strings doesn't mean they're inherently weaker.
And I think that's where DB RK gets the huge advantage. Not only the build benefits greatly from the gear and can hold on its own, but it's become next to overpowered when combined with buffs like Magic String.
There are more scenarios where a physical build outperforms a DB one than simply enemies resistant to Fire/Water/ranged damage, all of which aren't as rare as you think. The biggest one is that a physical build outperforms DB when single target dps is more important, i.e. against the majority of instance MVPs. Mobs weak to a certain element DB isn't able to exploit is another example.
Physical RKs have plenty of places to shine. Your continued denial of this fact gives off a very heavy impression of ignorance. Seems to me you don't have much experience when it comes to PVM/MVPs outside of leveling because most of your statements are downright incorrect. I also don't understand how you can judge a build so thoroughly without having played it to an adequate level. If you don't know what you're talking about I'd recommend you not give false advice.
Like I said, I am open to hear what areas which Physical RK can shine that are out outperformed by other class/builds. At its current state, recommend Physical RK is almost just as a bad advice to many newer and poorer players. If there are sufficient evidences that says so, I am more than willing to accept it. I honestly would enjoy playing Physical RK as long as it's not so much about two button spam, but that's Ragnarok Online for you.