this is a response to bigfoot and elevator music's 'grachomp is uber' threads from a few pages back (I think pg 28). I think they' both have some good arguments for why chomp is uber, at least they made me rethink some stuff.
To summarize and extend the arguments of em's post:
1. Chomp can be a bit like wobbuffet, it can come in and take out a poke early game with relative ease unless you have skarm and even then...
1b: garchomp is very hard for stall to deal with because if it comes in before toxic spikes are on the ground, you basically need to go to skarm/hippow and phaze it away. this 'need to phaze' points out that chomp is actually a very good early game sweeper/wall breaker. (something I'm trying to say it isn't).
2. chomp, because of its defensive versatility (this is my way of saying it can hold scarf, or 3 different kinds ofberries, each of which requires slightly different ways of defending against it ) combines with its offensive power makes the metagame stale because you need many chomp counters.
Delta2777 and bigfoot both extend elv. music's post, especially point 2. I'll just quote bigfoot's last paragraph, you can read all his math of pokes that check chomp:
For needing to choose three checks from a small list of possibilities, Garchomp fits the Offensive Characteristic. This forces drastic changes in a metagame where half of these checks are seen on less than 7% of current teams. In playing the suspect metagame, many of these checks are seeing huge jumps in usage. Skarmory, Bronzong, Scizor, Latias are all being used much more than in a Garchomp-less metagame, showing just how necessary it is to use these checks. Of the other checks, most have not fallen in usage. This shows the increased usage of Garchomp checks--and not by a small amount (Skarmory usage in particular has skyrocketed). The induction of a new, powerful Pokemon into OU should cause changes, but not the extent that Garchomp forces.
This point is basically that chomp in OU is best dealt with by anti-chomp teams, rather than by any number of general strategies.
Here's my response:
I want to think abt how chomp does against certain kinds of teams, stall, semistall, heavy offense, balanced/bulky-offense, rather than specific pokes. I think it makes more sense to think about how a pokemon impacts kinds of teams/strategies in the ou tier, rather than thinking about what counters/checks it on a poke-by-poke basis. Most of the uber pokemon would make particular kinds of teams very very very hard to use.
To give a sense of what a poke that meets the uber offense characteristic by a lot would do, think of kyogre. I'm specifically choosing a poke that doesn't really resemble chomp here. Ok, so there's an uber warstory in the archive bwtn gen emp and panamaxis. In it, pana's kyogre is paralyzed very early game but still manages to take out or force out a bunch of gen emp's pokes, despite being fully paralyzed a couple of times. In OU, such a pokemon would basically have no probelm coming out on turn 1, and winning the game unless the opposing team was full of kyogre responses. Even if you throw up light screen or use amnesia or something, kyogre can just bide its time firing surfs or calm minds or whatever. In other words, no kind of OU team besides a team designed purely to counter kyogre would really stand a chance. This is what over-centralizing would be like, and what breaking the offensive clause looks like.
if elev. music is right and chomp makes stall unusable then he should be uber. The problem for stall teams facing chomp is that tspikes are needed to beat it, but every common user of tspikes (except for maybe smeargle before his sash is broken) will basically always be set up bait for chomp (outside of a sandstorm, roserade can sleep/paralyze chomp, she can also hit it with a very strong leaf storm, but chomp has a good chance to ohko her first). Now most stall teams don't use reflect. it seems to me that with chomp around, setting up reflect becomes pretty necessary for stall because it lets you set up tspikes behind the reflect. reflect turns every pokemon that isn't weak to one of his attacks and/or has decent defenses into a chomp counter. Before someone says "but chomp can boost his attack to get past reflect" yes. But that uses up turns that your bulky attacker can use to hit chomp with one of the many attacks he takes neutral or super effective damage from. so you reflect early game, set up tspikes, and stall chomp out when he comes back in. i know that few stall teams use reflect now, but it doesn't seem over-centralizing to me.
the other problem chomp makes for stall teams is that it really benefits from, as opposed to being hurt by or not affected by, sandstorm. Stall teams might want to rethink using hippo/tar early game to set up SS. One potential idea is to think of making a stall team that uses a different kind of weather, hail stall can work (ladybug's team proves it), and rain-stall might be a very strong possibility, esp. if manaphy is ou. This could be a bit of a stretch, but i don't think chomp would enjoy sweeping in the rain or snow.
Heavy offense teams don't really have much of a chomp problem in my experience partly because they often set reflect up early game and they threaten too much with there own pokes to give chomp much of a chance to set up.
what about the need 3 counters/stale metagame argument?
I could be wrong but it seems to me that chomp will always go down to:
2 ice attacks, 2 dragon attacks, 1 ice and 1 dragon attack, 2 powerful unresisted special attacks, 2 powerful unresisted physical attacks.
This is important for bulky offense,semistall, and heavy offense teams. It indicates to me that what you need for chomp is 2 checks. I think the argument could and is being made that chomp's ability to relatively reliably take its check out makes it uber. That said, if my team has 2 pokemon that either outspeed or can take a hit from chomp and hit chomp with an attack described above, I should be ok. The counter to this is that chomp can always switch out and come back in. My response would be that in the mean time my team has the chance to set up a situation where chomp won't be sweeping much, either by setting up my own sweeper, toxic spikes, reflect, whatever.
like i said at the start, i do really think that el. music and bigfoot and delta2777 have a good point, this is just my response.