So if one pokemon loses to one of its counters 72.1% of the time without the counter even having to alter its normal moveset and EV spread and only if it comes into a SpDef drop from Seed Flare, you think it should be Uber? I'm sorry, but since every argument that you've given has either been refuted already or is blatantly false I have to assume that this is what you're thinking.
I was discussing why Blissey wouldn't be considered counter status. 29.7% is enough to counter; it just should be backed up by a check that doesn't fear Seed Flare in case something happens. That was mainly because if Skymin doesn't have the 57.8% of KOing, she will swap out, and 19.5% residual damage on Blissey guarantees that Skymin can KO a Blissey swapping in 57.8% of the time, which Blissey always seems to have because she is almost always the team's only special wall. That 19.5% damage is easily done by a Timid Heatran Fire Blast.)
It's like why you can't have Hippowdon or Donphan as your team's only method of getting rid of physical Tyranitar (before Plat and Aqua Tail's introduction). If Hippo/Donphan had too much damage, he would be unable to swap into CB Crunch.
Basically, Skymin came into an environment that was already well-equipped to handle it. Skymin is not strong enough to power through its counters like Garchomp, Chomp is uber, it doesn't have the defenses or recovery to make it a force throughout the entire match, and it doesnt have the movepool to keep you guessing like Deoxys. Basically, it has no Uber characteristics EXCEPT Serene Grace + two annoying moves. Have you ever KOd a Blissey with Skymin? Yes, but not in that 27.9% scenario, in the 57.8% one. Would you risk it, knowing that you have a >70% chance of losing? That would be like staying in on Heatran knowing that there is a 15% chance Fire Blast will miss, would you do that? Of course not.
Even with Stealth Rock damage and 10% damage before it comes in, Blissey will still survive two Seed Flares on average, even if the first one drops her SpDef. If that isn't a counter in d/ps fast-paced metagame, then nothing counters anything and the entire word can be thrown out the window. There is a reason why OU has a physical bias, and Skymin exemplfies it. Special attackers in OU are simply too weak to be "broken". 120 base spatk is not that much without any good boosting moves, especially when you have two of the worst STAB types in the game.
Also, there is a difference between "I think its flinch rate is too high" and "I think it's Uber". If Skymin gets banned simply because of the "luck factor" then we will have to drastically change the game we are playing. No more Togekiss, Jirachi, pokemon with Sand Veil, no more Absol, etc.
A large part of the luck factor includes what happens if the hax occurs. If a Gliscor counter e.g. any of the bulky waters miss a Surf on Gliscor, it is very unlikely that Gliscor will be able to pose a threat with Earthquake. Such a miss means little, especially compared to a flinch that results in the opponent being killed. This is part of the reason why OHKO clause is applied, as that 30% chance results in a KO. Same goes for Evasion Clause, but not as strongly.
Togekiss and Jirachi need a turn to cast Paralysis to flinch most things. Skymin doesn't need paralysis support except against Scarfers, Jolteon, Aerodactly, Crobat, Ninjask and Electrode. Paralysis can also be blocked by Ground Pokemon, Electivire and Jolteon (Ghost in the case of Body Slam) and healed by Rest, Aromtherapy or Heal Bell, whilst the only method for blocking flinch is Inner Focus (Lucario, Dragonite and Crobat are the only notable pokemon that can do this). And Absol only has 12.5% of critical with Scope Lens and Sucker Punch (without Sucker Punch, a lot outspeeds Absol).
Most of the pokemon who have Zap Cannon are Electric pokemon, who can threaten others already with a strong electric move and Thunderwave, so those who would fear THunderbolt would fear Zap Cannon. Plus Zap Cannon is completely blocked by Ground pokemon (and there goes the element of surprise). The closest exception in OU is Forretress, whose Zap Cannon would only really hurt Gyarados (and Skarmory). But this weakens Gyro Ball's power and Forretress has a poor SpcAtt to use it with.