I have played a number of test games using the voted spreads and abilities. These test games are, naturally, biased data, in that they are played in an environment where 30i/b are both very new and at the forefront of most of the participant's building, in addition to including a lot of mirror matches. With that disclaimer aside, the impression I have gotten is that 30i is honestly quite passable with only Roost + Brave Bird, and really does not need that much help, beyond the issue of where it fits onto a team.
Taunt as a move does worry me to some degree, as it does allow us to easily win 1v1s vs something like Skarmory, and Toxapex 70% of the time, however it also opens us to completely wasted turns, eg an opponent going into Pult/Zera/Weav on a Taunt turn typically will mean at least 25% damage (aka SR) on us. In this way I am open to Taunt, even if I view it as unnecessary.
Swords Dance is where I do get worried, as while it does have the same risk of a wasted turn, if predicted correctly it allows us to easily bypass Toxapex, and really removes a lot of the opponent's ability to try to pivot around us. The inclusion of Swords Dance means that an opponent suddenly takes on a very large amount of risk by trying to scout us with a U-turn Landorus. Unlike Taunt it also synergizes very well with Substitute, a move that we are very likely to use. Unlike Coil, Swords Dance manages to clear the threshold to KO Toxapex with a +2 into a +0 hit 100% of the time with rocks up. Swords Dance also means that we are unlikely to be able to give any priority moves, which, while a very, very, very minor concern, is also worth considering.
I should note why I think scouting us with Lando/Pex/Bro is useful, and something I think we should preserve. Currently a lot of our counterplay is going to be faster pokemon such as Tapu Koko, Zeraora, Dragapult, and Weavile, all of which we OHKO from full HP. By preserving this method of scouting, we ensure that an opponent can take us on with those without simply having to risk a OHKO on a missed prediction. Frankly it should also be noted that Lando, Pex, Bro can only scout us in this manner a small number of times, eg meta lando taking 40% from BB.
Neither of these moves are likely to make us overpowered, as the vast majority of our strength is tied into Roost + BB, but it could complicate our counterplay, and doesn't really solve the issue of "why is this on a team". I would prefer to go with Taunt out of the two, but I would really prefer to lean more into Utility, and give us options such as Stealth Rock, U-turn, or Defog (rocks probably better because of how team dynamics will work given our typing).
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I have seen some people arguing for Court Change. Court Change is a move that is ineffective on this Pokemon. The nature of our inability to hold HDB means that we need our side of the field clear of SR to maximize our lifespan, and while Court Change can do that, it can only do so once. If rocks go up twice, we are suddenly back into our original predicament, and we get worn down in a matter of turns. Court Change is not a move we should realistically consider.
I would also warn against trying to give us signature moves for the sake of giving signature moves. Oblivion Wing had a similar push for no reason beyond opening up frail special sets a bit. A minor goal should be pursuing verisimilitude, that is, we should try to make CAPs using tools that are widely available, rather than giving out signature moves which will make our Pokemon look less legitimate.
and 
are doing jack shit to us and 
has to rely on Scald burns, and if we have substitute, then its in the same boat as the other two) and it really feels like it just turns the match-up into having to rely on a 50/50. There is also the potential issue of how Taunt + Set-Up would affect 30b, and to be honest, I would rather just deal with the issue regarding Taunt now so that we have more time to discuss other aspects of 30b.
