Opportunity cost is one shitty argument. If you're running ekiller then you lose out on running cm ghostceus or sd ghostceus or support ghostceus or hail iceceus or sd dragceus, etc. So regardless of the form it still has massive opportunity costs. Not to mention we're rating mons as a whole not individual sets. SD/filler/filler/filler normal ceus is one of the sets normalceus can run it isn't normalceus itself.
As for your ghostceus argument, he lacks an item bar spooky plate. Not to mention that 252+ speed statement makes no sense whatsoever. Smogon's analysis sets aren't the only sets out there. What stops normalceus from running lefties/scarf or whatnot to help cripple attackers or prolong its longevity? Nothing unlike ghostceus. So if you're really going to make an argument for ghostceus please don't use some one sided crap. Bulky arceus isn't that sturdy just fyi.
Is jolly ekiller a thing now? News to me. Sorry for being completely unaware of how amazing 252+ speed ekiller is (hint it's not). Defensive latias don't really care for a burn and can just phaze ghostceus and/or setup light screen if needed so don't see an argument there. Offensive latias just sucks (lol @ getting 2hko'd by kyogre's scarf ice beam). Latios is a bit of a tossup anyhow with neither being able to ohko the other while latios can significantly dent ghostceus. Honestly a bulky ghostceus will beat latios 100% of the time while support ghostceus is forced to heavily predict. Overall it works as a check but not really a solid check.
Eh I just listed random shit of the top of my head. Overall it bashes the point that cfdu made of normal ceus comprising of well ekiller and its variants and completely ignoring every other set which is absurd. Should've mentioned band but oh well. inb4MM2saysekillerisntrevengingcrap
252hp ev's will still get you 2hko'd by the most prominent uber threats iirc. Hence why I said 252hp/252+ spd for a supportceus is garbage and it's more favorable to go for a spread similar to err 252hp/40def/160+ SpD/56spd or if you're more physically inclined switch the def and the SpD evs around. A support mon getting 2hko'd isn't much of a support mon at all.
First of all, Support =/= wall. A support mon is used to provide utility for your team, not to absorb powerful attacks. And here lies the ranking difference between the two Arceuses. Arceus-Ghost provides general utility to your team, being your spinblocker, checking things with will-O-wisp, holding the team together thanks to his useful resistances. How is Arceus-Normal supporting his team with his shitty typing, when you can use other Arceus forms? Setting up SR? There's only two advantages that Arceus-Normal has over his other forms, which are: 1) ability to hold an item 2)Stab on Extremespeed.
When you use Arceus-Ghost, you don't have an opportunity cost. No pokemon can do better than what he does. Extremekiller has little opportunity cost, as he has a wonderful niche in a decently powerful priority STAB. Now, when you take Arceus-Ice (it's your example), you're better using Kyurem-W + another arceus form. So no, not every Arceus forms have an opportunity cost, your point is invalid.
You're better using Overheat or Lum Berry on Arceus to mess up with his counters, even if it relies on Sun support or Spikes support. BandTrickArceus is kinda effective if the opponent is using Skarm/Giratina as Arceus's counter, but is highly ineffective against offensive teams that use pokemons such as Terrakion to deal with Arceus. Defensive Giratina-O, another counter to extremekilller, is immune to trick, same with Arceus-Fighting.
And lol @ 120/120/120 defenses not bulky. If 252HP Arceus isn't sturdy, then I don't know what to say. Besides that some people uses Extremekiller's bulk, which consists of 88 Evs in HP (it's the standard set fyi), as an argument to raise him to S-Rank.
Tell me one Calm Minder in Uber who can beat specially defensive Latias besides his brother Latios.
What's your point telling me Arceus-Ghost is a shaky check to Lati@s? Even if your argument was correct it won't help the case of Arceus-Normal. There's a move called recover that Arceus-Ghost can use when he switches into Latios's Draco Meteor, since
he outspeeds with 252+.
Offensive Latias is always eved to avoid the 2HKO from Kyogre's Ice Beam. Otherwise use Latios.
120 speed is very good, and anyone using Arceus should take advantage of his speed, even though some Arceus might put a few Evs into defenses, like Arceus-Grass, in order to avoid some important 2HKO. Remember in Gen4 when Lugia was eved to be faster than Garchomp? People did that to mitigate some damage by setting up reflect before, or to use roost before taking another attack. That's exactly the same thing, it's always better to cripple a pokemon with burn than having to take an attack before burning him. You can recover before taking an attack, or even Ko the opponent, which you could not have done if you had run less speed.
