I would still err on putting Swampert to A- and Pelipper to B+. Pelipper is the only u-turning auto weather setter in the game, which is inherently such a huge boon to the core.
I can see why people might think 1 slot up for Swampert might be enough for now, but it doesn't get there without Pelipper, who has really begun to shine on its own recently, and is no longer just a 6 turn bulky weather pivot. No other combination of mons in the B tiers have the ability to systematically take down several top cores like these two do. Curious to see the rationale particularly behind Pelipper, who is league better than every other B mon, except maybe Latias who I've also been arguing doesn't belong in the B, but B+ instead.
Looking at these rankings has made me think also that the B+ ranking is getting a bit saturated, and I can see why people might not want to saturate it further. So I want to nom a few of these down, that no longer seem to fit in the top of B+
Hydreigon to B: No clue how a mon that is terrified of mimikyu, with a middling speed tier and okay offenses/coverage makes it to B+. I've played a good amount of hydreigon, and while it does fulfill the roles it takes okay, there are definitely better options available in the tier for everything it runs (better scarfers, specs wallbreakers, lures, Z move breakers, etc). It also really wants to run both fire blast and earth power with its choice sets, but has to settle with only one alongside dark pulse draco and u-turn, the biggest reason why it should be ranked down.
Skarmory to B: It remains a niche option for a lead on some hyper offenses and some stall builds, but come on, we've evolved past basic solerme offenses in 2019. If you want to consider its role in stall, all the other stall options are lower in viability (slowbro, quag, shedinja), and is clearly not the same level that Chansey is, another B+ mon.
Nihilego to B: unless your name is Zaaya and you get lucky and happen to face vivillon/volcarona in your invitationals match, chances are you have used Nihilego and found it was fucking useless. It can't take physical hits for shit, is heavily outclassed by other leads for getting up hazards, and never fails to disappoint with its lack of offenses. I often meme that its only viable set rn is scarf rocks, and weirdly enough, it might be, because it wants to snowball sweep and put up rocks, but can barely do either of them outside of its scarf set. But being a scarfer with rocks clearly has its issues, which is why this mon doesn't belong in B+.
Hopefully after clearing up B+ a bit, Pelipper can find a home amongst its rightful peers.