I agree with everything you say there about sportsmanship and gaming mentality, as well as finding a balance in your lists. One thing I do disagree with, however, is when you say OnG and Skaven are badly thought out armies. Now, granted, I used to play Skaven and now play OnG so i'm a wee bit biased, but to describe OnG as bottom tier is very harsh. Even without taking a 'hard-as-possible' tournament list it's still very easy to make a fun and competitive army. There are so many options and they all have a viable place (except Snotlings).
I've just started a fluffy SO army, and though i've only played a few games i've won as much as i've lost, and that's with a self-imposed handicap of no gobbos, no BO, no war machines, no Arrer Boys and only River Trolls. SO armies sound hard but if anything, as has been my experience thus far, they are one of the hardest types of OnG list to play due to frenzy on top of animosity. Even so, i've still found them very competitve.
As for Skaven, without doubt they are a top teir army, but they're by no means broken. Indeed, they are very beatable, and you have to consider that because they are a 7th ed army, some of their options are going to be a bit top-heavy compared to the more balanced 8th ed armies.
Even so, they are eminently beatable.