Inconsistent was banned on more than just theorymon. People who played/face it know how annoying as heck and cheap it was and how it turned losing games into winning ones and depending on ones luck absolutely made skill pointless.
That's a bold statement to make. You are asserting that the most skilled player would have a 50% chance to lose to a completely unskilled player if inconsistent is involved.
There is a LARGE difference between things like Confusion and Parahax or even annoying Shaymin-S flinch hax (which also got banned for that reason in addition to Seed Flare) and Inconsistent. Inconsistent has few counters and it's counters were...Inconsistent. Like a Clear Smog Poke could be destroyed if the Inconsistent User got a Attacking boost, Haze is only temporary and again with an attack boost, Whirlwind and friends had a tendency of MISSING when it got an evasion boost, it was nearly impossible to hit after evasion+Sub and Protect, Inconsistent users OUTSTALLED things like Calm Mind Latis and Zapdos (Octillery) and WON, Inconsistent had a fairly consistent chance of letting BIDOOF take out UBERS, Smeargle Inconsistent even more so with Assist Power and being able to Baton Pass Belly Drums and Shell Smashes in adition to Inconsistent boosts, etc etc etc.
Inconsistent ALWAYS happened. What the effect was you didn't know but it ALWAYS had a chance of doing something. That is a problem and in any game, things like this are broken because they're guaranteed to do something for NOTHING. -1 is not enough of a drawback on it, especially since it was possible to sub near infinity with Sub/Protect/Evasion together until you got +4s, +6s etc and sweep. And most of it's "counters" were entirely situational, just sucked, or were on pretty meh pokemon that died to anything non-Inconsistent. Inconsistent gives far too much power and advantage. Unbanning evasion has a far more likely chance of happening than Inconsistent (then again, Double Team isn't all that great but Minimize on certain things named Chansey/Blissey would be ARGH, especially since Minimize is +2 now).
I somewhat agree here (at least about octillery, as it was actually tested) except for two things. One, people in general did not play against inconsistent correctly. Very often when I used it, people attempted to set up on the user rather than just attacking it, which was very suboptimal, as the inconsistent user "automatically" sets up so it gets maxed out faster. Just because you think you should be able to set up on octillery doesn't mean you are actually able to. Next, who are you to say how good a pokemon "should" be? If bidoof is good because of its ability, then bidoof is good because of its ability. There is nothing inherently wrong with this. Shedinja "shouldn't" be able to counter and take out kyogre, but only its ability allows it to do so.
Also, I never came across this situation but I would guess you are exaggerating when you say bidoof could consistently take out ubers ._.
In regards to your points about evasion, if you think evasion is OK on some pokemon but not others, wouldn't that suggest that the pokemon, and not the move is the problem?