Interesting analysis, thanks for some new thoughts! While investing in most altcoins is like a gamble, and you are right that bitcoins should be the main part of the portfolio, I will suggest also to take a closer look into next generation of coins - NXT, new protocols over bitcoin like MSC and XCP, and few coming projects.
And by the way, what do you think about Darkcoin?
Seconded. I've been watching Darkcoin for some time from afar... would be interested to read an educated assessment of it.