Alright, got my thoughts down here.
Just some quick reasonings (he said thinking he wasn't going to be monolouging):
Unlike fp (sorry, Clyde), I don't think anything is S tier in this meta. Everything in the tier has flaws and have legitimate reasons why you wouldn't use them. Closest is maybe bisharp, but it is a big tera hog and can feel dead weight into bulkier teams (mainly stall) at times.
Despite this, there are multiple A+ tier mons in the tier, with all of them very splashable and contributing a lot to battles. Main weird picks are jirachi (cm rachi is lowkey a bit broken) and fezandipiti (u-turn until you can cm, then profit).
A tier mons are a step below the A tier mons, but are still extremely great. Main mons in the tier are conkeldurr (disgusting mon against fatter playstyles while having utility against faster teams) and hippowdon (run rock slide or ice fang, its still an amazing wall).
A- tier mons have genuine flaws that hold them back a bit, but have really good upsides. Main mons in the tier are vaporeon (insanely crazy defensively, and enables a ton of dangerous shit), rhyperior (great mon, but is stonewalled by a couple of really important targets and has some 4mss) and chesnaught (insane role compression and walls a lot of amazing mons)
B+ tier is mons that have less upsides then A- tier, but still can perform really well. Main mons are flygon (just doesn't do well enough in any one category to not be outclassed by other grounds), porygon-Z (insane sweeper that doesn't add a lot defensively, but still really good) and oricorio pom pom (yanmega junior, but balanced).
B tier mons get into the "you can use these on a team and they can work well, but other mons do outclass them a decent amount" Main mons here are A-muk (really great ghost answer that can have a suprising amount of flexibility if you look deeper), gallade (really great fat answer that has options against faster teams) and mowtom (abuses a lot of people prepping for rhyperior while also doing well against rhyperior itself).
B- tier mons aren't necessarely bad, but just outclassed or have significant flaws. Main mons in here are chandelure (really great spinblocker that exerts a ton of pressure), cress (only reason its not C tier is cause of lunar dance, but I'm using a better mon 9/10 times), kilowattrel (stop saying rhyperior, kilo can get around it) and infernape (insert potential man joke).
C+ tier is going onto the mons that are bad, but still have a few upsides. Main mons are torkoal (better then tales, due to spin and body press), scrafty (amazing fat destroyer that can check bisharp) and bronzong (amazing rhyperior answer that can have a ton of utility).
C tier is where we get to the bad mons. You won't use these mons often, only once in a while to fill specific roles in a team. Main mons are cincinno (maushold with knock is alright), cloyster (bad shell smasher, was close to putting it into UR but its power is good) and grimmsnarl (guille popped off with this, but nobody else has used it so eh).
UR are for genuinelly bad mons. I can't see a reasoning to use these mons on a team as they are liabilities if anything. Mons here are forretress (good role compression, but always is setup fodder for something due to its 4mss, and is outclassed by most walls/spinners. Only use it sometimes on weather teams), galvantula (love you buddy, but bee outclasses you almost entirely), kingdra (just run hersculegion, that speed and dragon stab is not enough of a differentiating factor), indeedee (run armarouge in another teamstyle and it will prob do just the same amount of work, plus indeedee lets in way too many powerful mons), vileplume (worse amoonguss, and bisharp is its father) and incineroar (def the best of the UR's, but its just outclassed by other dark types)
Mew/Reva would prob go around A- range.
Electric types are a lot better then people give credit for, not many of our ground types stop them too well (and the ones that do people don't seem to want to use for some reason, please use hippo). No, rhyperior dropping doesn't make kilo or heattom unviable, just run u-turn/t-blast or wisp. And besides rhyperior doesn't have the best longevity so it can be chipped down.
Spikes is def the way to go, best playstyle in the tier. Despite this, every major playstyle is viable.
Nothing is banworthy besides maybe armarouge. Every other candidate like bisharp, slowbro, volcanion or suicune is fine, and has drawbacks that hold them back every game.