That's not a critique of the argument, instead it's ad hominem.
I didn't have an argument to critique. Your 'argument', at least up to this point, is 'Alexander benefitted from his father's death (and I personally have a strong animus against the man) so clearly he did it'.
Don't flatter yourself - that's not a serious argument, and no-one here will take it as such. Throwing in allusions to Stalin, Kirov and any other historical figure you can think of doesn't bolster the flimsiness either, it just makes it look as if there's a lack of detachment and perspective, as it would if somebody started comparing Pompey to Hitler.
And no, incidentally, it's not an ad hominem, since I didn't mention you once, only your argument.
The comparison is to Nikolaev's assassination of Sergei Kirov, which could only have been ordered by Stalin, but where he was not directly involved.
Well, for one, we don't know for certain that Stalin ordered the killing of Kirov. It's not a fact. It's a strong,
overwhelming likelihood that he did, if nothing else than by the simple nature of the state that Kirov inhabited.
But quite where the comparison here is to the killing of Philip, I haven't the slightest idea, as there is no overwhelming likelihood of Alexander being involved, and nor was he the only one who could have ordered it. He might have been involved, and you can make a decentish argument to that effect. (It's not the one you've generally been making, but it's out there.) But overwhelming, no, not remotely.
Ah, he'd already proven his skills as a tactician,
He had been in one campaign, IIRC, against tribes to the north by the time Philip died, and of course participated at Chaeronea. He was essentially untested. If he was already regarded as such a genius by the time of Philip's death, then it seems odd that the whole of Greece immediately and confidently rose on the news, and Demosthenes was able to charicature him as a feckless flaneur.
did not like daddy's choice of wives,
Not really sure what this is based on, or why it's relevant.
and was fearing his own eclipse in the event that Philip's new wife would have given him a son with a stronger claim to the throne than Alexander's ... Alexander ... acted as he did from a rational set of political conclusions.
Even assuming Philip could produce an alternative heir, (and it's worth pointing out that he probably had about half a dozen minor wives other than Olympias already, and had already produced another male child) said heir would have to grow into a man before he became politically viable; that would take decades. Macedonia is not medieval western Europe, there's no sanctity of kingship, and only men reign, not children. (Or if they do, then they are swiftly supplanted by their royal male relatives, as, indeed, Philip had done with his nephew Amyntas; yes, I'm afraid darling Philip was a usurper) By the time of his death, Alexander had been reconciled to Philip. There wasn't the slightest chance of Alexander being supplanted as senior heir in anything but the wildest long-term, and then it was only a possibility; even if Philip had taken a knock to the head and somehow demanded of the Macedonian elite that they recognise a babe as his heir, then it would have made no ultimate difference, as simple political reality would have won out in the event of a vacancy. Alexander is supposed to have named 'the strongest' as his heir on his deathbed. If he did say that, then he was simply recognising the Macedonian reality of power. The idea that Alexander was under imminent threat of being rendered politically obsolete is utter nonsense derived from an anachronistic understanding of the period.
I guess this rational objection can be overriden though by the fact that Alexander was one of the most evil men in history and was so psychologically buckled and bent by paranoia he couldn't walk straight.
