I agree that Alcibiades had many flaws. I also agree those flaws contribute to the lack of respect Alcibiades receives. They also resulted in the biggest mistake Athens made, turning their backs on Alcibiades a second time.

As for the delays, I must say that I am torn. Lamachus' plan was to attack the Syracusan forces immediately. Thucydides did state that this would have been the best course of action. I am not so sure. When Athenian forces did attack and defeat the Syracusan force, the Syracusan cavalry was able to provide an effective screen and allowed the army to retreat back inside the walls. Athens had sent only a miniscule cavalry force (50 men, if memory serves). These were unable to counter the enemy cavalry. So Lamachus' plan may well have been just as ineffective had they tried it immediately.

Alcbiades' plan was to gain the support of the local cities who opposed Syracusan power. In addition, he hoped to gain the support of the Sicels, the natives who had suffered greatly from Syracusan power. The Sicels and others could have provided the Athenians with the needed cavalry. In addition, gaining a safe harbor for the fleet was paramount, in Alcibiades' opinion. Both safe harbor and cavalry could be gained and the Syracusan's were unlikely to gain in strength in the meantime.

In all probablity, Alcibiades' plan would have worked. The Naxians joined the Athenian alliance against Syracuse almost immediately. Catana too fell into line. Only Messana did not join immediatley, but Alcibiades had communicated with a pro-Athenian group within Messana who had plans to overthrow the city and join with Athens. Given a little more time, Alcibiades would have accomplished his goals of bringing much of the island into an alliance against Syracuse, gaining a safe port and gaining the cavalry Athens needed to counter the 1,200 strong Syracusan cavalry.

My extra point is this: the Spartans had been talking about fortifying Decelea for some time. That they had not done so yet was in keeping with the cautious Spartan mentality. Nevertheless, with or without Alcibiades' advice, it is likely that the Spartans would have gotten around to fortifying Decelea. Alcibiades' involvement in this was probably less important than the sources seem to indicate (a result of Alcibiades' arrogance, possibly, for he could easily have taken credit for it when he was interviewed by Thucydides, if he in fact was interviewed by Thucydides).

Extra point number 2 [sorry :-)] : Alcibiades was arrogant and self-serving. But I would argue that these were not uncommon character traits among the Greek elite. Pericles shared the same traits, as did Lysander, as did Astyochus. I think the sources show Lysander's greed and arrogance as much, if not more than those of Alcibiades. While Lysander cannot be said to have ever truly betrayed Sparta, he certainly betrayed Sparta's best interests in favor of his own. Astyochus on the other hand can be said to have betrayed Athens when things went against him as well. Alcibiades' bad name stems less from his inherent flaws (which he definitely had) and more from moralists like Plutarch and others who highlighted them in order to make a point.