:smack:
Even if there were no issue about a predicate nominative, I would argue that a transitive verb would take the entire clause as its object and therefore the “whoever” would still be nominative. But I can see that being argued either way. Given the word “is”, however, there is no validity to this correction.
I believe you mean pendant. (Though why being called a type of necklace is considered an insult,
I’ll never understand.)
If you’re going to be a pedant, you’d better actually be correct!
That should read
“you actually should be correct.”
“Even if there were” sets out a hypothetical condition, so “I would argue …” is correct. But how on earth do you get “transitive verb would take …” and “‘whoever’ would still be …”? Those are not subordinate to the hypothetical. What you’re trying to say is that if there were no such issue as you describe, you would – in that hypothetical – make a certain argument, and that argument would be “that a transitive verb takes the entire clause as its object and therefore the ‘whoever’ must still be nominative”.
The point being that, by your own statement, whether the hypothetical is true or not, your conclusion is invariant and not hypothetical. And whether or not you choose to wade in and make your argument, the conclusion remains invariant. So the use of the hypothetical forms “would take” and “would still be” is incorrect.
So you’re wrong. You done writ badly-like.
Regards,
A pedant. 
Bad, bad, bad.
“Whoever” was correct to start with.
Whatever.
What he said.
Also, why are you bringing your Twitter-fights here?
I believe you are also incorrect in your pedantry. 
Here is the sentence:
“Even if there were no issue about a predicate nominative, I would argue that a transitive verb would take the entire clause as its object and therefore the ‘whoever’ would still be nominative.”
Perhaps it would have been clearer if I had written “I would argue that even if there were no issue about a predicate nominative, a transitive verb would take the entire clause as its object and therefore the ‘whoever’ would still be nominative.” But there is no fundamental grammatical reason my chosen word order cannot also be correct.
Yes, that is my point in a nutshell.
Ok
No. Think of it this way: according to your analysis, in what situation would a transitive verb NOT take the entire clause as its object in that exact set of circumstances? Your use of the conditional implies that it depends on whether you choose to make the argument or choose not to bother making the argument. It doesn’t. Your analysis is either right or wrong, period. Therefore, the use of conditional phrasing on how to structure the sentence is incorrect.
Anyway, I was just making a lighthearted joke.
I know, hence the 
But since we are haggling over it just for fun: the protasis here can be paraphrased as “if the verb were transitive”, and the apodosis is essentially “I would still have an argument to make as to why the use of the nominative was correct”. It is not a transitive verb, therefore that argument is superfluous and I don’t need to make it.
It’s not clear what you’re trying to say here. Yes, whoever is correct, but it has nothing to do with whether the sentence as a whole is a predicate nominative or not. The reason whoever is correct is simply that it’s the subject of the verb make (not the object), so the pronoun takes the subject form. The rest of the sentence in which the clause is situated is irrelevant.
I don’t know if that’s what you were trying to say, but if it was, it didn’t come across very clearly.
To provide some examples:
whoever likes Madonna (i.e., Madonna fans)The pronoun is the subject of the clause (the subject of the verb like), so in all of these various larger sentences, it doesn’t matter. The pronoun will always be in the subject case:*The members of the club are whoever likes Madonna
The club welcomes whoever likes Madonna.
Whoever likes Madonna can join the club.
For whoever likes Madonna, that CD is a classic.
*Now let’s consider a clause where the pronoun is object case:whomever Madonna likes (i.e, people Madonna is fond of)Here the pronoun is the object of the verb like.*The members of the club are whomever Madonna likes
The club welcomes whomever Madonna likes.
Whomever Madonna likes can join the club.
For whomever Madonna likes, that CD is a classic.
*The larger sentence is not the issue here.
When they hang you for being a grammar nazi, then you’ll be a pendant. A pendant pedant, in fact.
What “Twitter-fight”? That tweet was not in reply to anything, and has not received any replies last I checked. It was just a way to put the images somewhere so that I could post them here (and yes, I know many people use imgur for that, but why bother?). If you look, you will see that I tweeted it literally seconds before pasting the link here. I have done this several times when I had some kind of image I wanted to talk about here. If someone happens to read the tweet on its own, that’s fine too, but not my purpose.
Perhaps not, but yes: that is what I was trying to say: that if the sentence ended after “whoever”, it would be correct because it would be a predicate nominative. But if the rest of the sentence were the same and “will be” were changed to a transitive verb, it would still be “whoever” because it is the subject of the clause.