@ Admiral Korski:
You make good points, but after reading your initial arguments, I am curious as to why you do not mention the handling of Defensive threats. It seems that you focused way too much on handling attacks and such and not the entire metagame. With the greatest of respect, do not forget the presence of Defensive threats roaming around, like Swampert, Blissey, Skarmory, and others. What will the Steel resist help with there? Sure, CAP 10 may be initially thought of as a counter to top-tier offensive threats, but according to the Concept itself, it must be able to counter any Pokemon individually. That includes Defensive and Stall oriented Pokemon, yes? The Steel resists would be a non-issue for this point, and near completely useless (except with the immunity of Poison and the immunity to Sandstorm, although since CAP 10 is a counter type of Pokemon, I sincerely doubt it will stay out for more than a turn or two per switch). Can the Steel typing benefit against Stall, Trap, and Wall Pokemon as much as a more balanced typing can? I feel that by choosing Steel, we would then be overcentralizing on offensive attacks and not passive damage, like Pokemon who focus on phazing and status as forms of damage. To me, a type like Electric is balanced enough to take on all spectrums, because of not only the lack of weaknesses to all moves bar Ground, but because of the neutrality its Electric type attacks offer as well. It is therefore more balanced to give it the opportunity to take on individual threats offensively AND defensively. Having a ton of resistances doesn't mean it has the potential to retaliate well through typing. While this can be addressed with specific moves, we can only go by what the main typing is. With even three or four weaknesses, we will then have a harder time trying to individualize against top tier threats. Resistances are nice, but with CAP 10 focusing on individualizing, we want it to come in on every type of Pokemon and have some way of crippling it. Not just to come in on resisted moves.
Now, to your arguments:
Arguement #1:
Good point. A lot of the top used OU Pokemon are Steel types. However, look at your four examples. We'll throw in Skarmory too. Now, let's look at the Steel types of UU: Registeel and Aggron. What makes these five so different than the Steels of UU? Their secondary typing. Would Jirachi be better handled if it was weak to Fighting? Of course. But, the Psychic typing reduces the amount of weaknesses that it encounters from its Steel typing. Empoleon gets rid of Fire, as does Heatran. Skarm removes Earthquake and takes neutral from Fighting. Scizor (and Forretress) take neutral from Fighting and Ground. To be honest, it seems that the secondary typing is what makes the Steel types of OU so great. Look at Registeel: it's weak to all three of Steel's weaknesses, all common attacks in OU. Without a secondary typing, Registeel is completely limited in the OU environment, thanks to the presence of Infernape, Machamp, Flygon, etc. That, to me, shows that there is something indeed troubling about starting out with a Steel type. Therefore, I agree that for a Steel Utility Counter to work, it is absolutely necessary to have a second typing. Whether this limits options in upcoming polls is purely opinion, however.
Arguement #2:
I am no expert on the CAP Process, nor have I been here for a great amount of time. However, if we are trying to implement CAP 10 into the standard metagame, we should follow the limits that other OU Pokemon adhere to. You don't see Starmie getting Earth Power so it can deal with Electric types. I don't believe that we want to give CAP 10 a ton of moves and abilities to make it different than what its typing suggests. We might be able to give it whatever we want, but we should be reasonable as well. Giving something like Will O' Wisp on a Steel type would be irrational. The typing should reflect the kinds of moves it has, in my opinion. Steel has few support and offensive options outside of Toxic, Roar, Earthquake, and other common things. This isn't an argument as to why Steel typing is bad, but rather to state that we shouldn't immediately dismiss the negatives of Steel, or any other typing, just because we can add moves and abilities of any nature.
Arguement #3:
I see a problem with this line of thinking, however. For CAP 10, there will be no mystery as to why it's being used. If you switch in CAP 10, there's a good reason you did: it counters the Pokemon. Your opponent will know this, and switch out to another Pokemon. The one fault I see with this concept is the fact that CAP 10's purpose will be easy to spot once it switches in and uses an attack. While it's true that you can play mind games, remember that while CAP 10 can individually counter any Pokemon, in return, any Pokemon has a chance to counter CAP 10. A good switch, and CAP 10 is useless. This is why eliminating the number of weaknesses is of greater importance than increasing the number of resistances: we want it to be able to counter the opposing Pokemon with as little of risk of taking huge amounts of damage as possible. Switching in on a resisted attack is nice, but having a counter switch in who can easily deal with your weaknesses is not. This is why I support Electric and Poison. One weakness (two for Poison), a few good resistances, and great neutral coverage both offensively and defensively.