Your argument has no place here. First, you're limiting parses to the top 50. Second, you're discounting how completely irrelevant the top parses are with these added item levels. Third, you cite Norushen which requires the mage himself be the one who logs, which many do but I would not consider that to be a valid frame of reference.
Most importantly, you're telling people to go 14242->mastery as though you're up to date on the latest theorycraft. At item level 580 we began to see how crit damage amplification on PBoI began to change the scaling of crit when coupled with high mastery or high haste. Min/max for either haste or mastery as item levels increase is very clearly showing a drastic gain.
14242 is a compromise point and definitely my recommendation until you're over 580, especially with a 4/4 upgraded PBoI. Water Ele damage increases roughly the same with haste or mastery, and is complimented strongly by equalizing the weight of crit (above shatter cap) with haste or mastery. LB/NT damage increases so drastically in haste builds that the value of the crits + amp makes high haste build viable as well. On the mastery max side of things, icicles become so hard hitting that by adding crit to frostbolt it outscales haste.
I really don't want you coming into my thread telling people 14242->mastery when the VP upgrades have clouded the issue. Further, the reason you don't see more frost mages up there yet is most of the ones I knew have all gone arcane because they assumed the upgrades will benefit arcane the most. Hell, that was my theory until I began to see how it improved my own numbers.
The best I've seen so far is 19347 haste -> 10k crit -> 8k mastery. I need a couple more weeks of VP cap to switch over to my 28k haste->crit build. I would really like if someone could do the 100% mastery -> crit build and report back, too.
What I promise the community though, is that if they stick to 14242, they'll never get any crazy parses.