regardless of what you may have "heard" it's easy to independently verify that heracross is going to be uu
according to
http://www.smogon.com/articles/tiers, a pokemon is ou if the probability of finding it on a team is greater than or equal to the sum of the same chance for every pokemon divided by 176.14073324. naturally, the latter is very very close to 1/176.14073324. if you look at the percentages in the usage stats, that corresponds to the chance of finding the pokemon on a given team -- there are six pokemon per team, meaning the percentages should add up to 600%. if you divide that by 176.14073324, you get the cutoff percentage. 600/176.14073324 = ~3.406.
note that there is some weighting of different months involved... but that doesn't matter for heracross.
june: 3.04%
july: 3.37%
august: 3.35%
since all three months involved in the tiering change have usages of less than 3.406%, there's no way any weighted sum of them could possibly be greater. since the gap is so large it means the approximations we took (assuming the sum to be equal to 1, using rounded percentages) are not significant.
also i did the calcs for every pokemon with the raw data and the real formula in excel and it turned up the same way :p
anyways something interesting i've been thinking about is that weezing will have to drastically change if it wants to beat heracross, just like it had to change to beat special lo venusaur. jolly +2 lo megahorn deals 57.8% - 68.3% to 252/0+ weezing which is obviously a 2hko, while weezing doesn't ohko with any attack... yeah that's right, it does 61.1% - 73.1% with hp flying. weezing will have to run physical defense if it wants to have any hope of beating heracross, not even to mention flame orb facade versions. and it will have to run something beyond restalk sludge bomb wow, which obviously messes with its ability to deal with venusaur.
same deal with arcanine... its most popular set now is specially defensive, but if it wants to properly deal with heracross it needs to run 176 speed jolly. that arcanine takes 51.8% - 61.2% from a -1 lo close combat... jesus christ it's not even boosted and it will do enough damage so that arcanine cannot switch in twice in a row while stealth rock is up even if it recovers. and now venusaur's sludge bomb will deal 45.3% - 53.4% which is a big healthy chunk of hp. which means arcanine will no longer be able to one set contentedly to deal with top threats... it'll have to specialize, which makes it much less effective at dealing with a single one.
to be honest i sort of like the metagame change that heracross will bring. at least we know we'll have one more vote before dpp ends...