i think it's difficult to come up with an all-encompassing philosophy. for example, while i don't play gsc AT ALL and don't have a history of playing it, it seems like there is a consensus that the objectively broken snorlax should absolutely not be banned. a similar consensus emerges with stealth rock in gens 4, 5, and 6. thus, even a very simple criterion like "ban obviously broken stuff" can become thorny. these preferences ultimately come down to doctoring the metagame to what we "like" regardless of sweeping tiering principles, and i'm honestly ok with that. "oh, this is inconsistent/there's a double standard!" isn't wrong, but the pokemon metagame is too complex to actually apply a universal standard in practice anyway. i think consistency is a good ideal, but this is our game and we're playing it for fun. if people want to keep snorlax, why not?
i view luck as inherent to pokemon, so i think we should only ban luck-based elements when they are BOTH luck-based AND broken. this is clearly the case with ohko moves, which get free kills on a coin flip. i think this is true of scald as well, though i won't get into the details here. swagger strikes me as distinctly not broken at all, but specific abusers are extremely broken. i did not pay attention to its suspect test at all, but it seemed like the blanket ban was done to avoid a complex ban, and banning the move had very little collateral anyway? (rip psych up + swagger regirock.)
on that topic, i definitely agree with the principle of avoiding complex bans, though i think that sometimes they are more efficient than more generalized alternatives. i think baton pass is an example a lot of people would use for this.
i think the big thing is that tiering has to be dynamic and, ultimately, done case-by-case. any philosophy we came up with in dpp probably wouldn't have had any clue what to do about swagplay or scald. if something seems broken, suspect it, philosophy be damned. i think our intuition as battlers can sometimes be difficult to make coherent with actual words (which i think is a part of the reason scald, and on the opposite end, stealth rock, have been such under-the-radar cases) but that shouldn't be a reason not to do something.
(speaking of dpp, this is pretty random, but i would by lying if i said that i'm not extremely curious how dpp would look if, instead of banning the dragons, outrage and draco meteor got banned. sometimes i wish tiering was a little more creative in this way. those stabs are ludicrously broken--freaking flygon can mow down all non steels with outrage, even suicune and cresselia x_x--and greatly restrict team building by forcing multiple steels. i think letting the latis, salamence, and garchomp back in with nerfs would be a cool "alternate universe" of dpp!)
Why are the beautiful sick and divided like myself?