1: Would your teams change dramatically if Garchomp never existed and if so, how?
2: Do you find yourself preparing for Garchomp more than other Pokemon when team building?
3: Do you have more than one way of dealing with Garchomp on your teams or do you have exactly 1 counter or 1 way of dealing with it?
4: Does Garchomp impact the popularity of certain sets or Pokemon?
5: Do you think there is any other Pokemon nearly as threatening or centralizing in the metagame as Garchomp.
1. Abso-fucking-lutely. Because...
2. I prepare for Garchomp on EVERY OU team SIGNIFICANTLY more than ANY other Pokemon, Gengar / Lucario / Salamence / Tyranitar / Deoxys-S / Wobbuffet included. In fact, I ALWAYS have a Steel on my OU teams SPECIFICALLY for Garchomp, and if the Steel isn't Bronzong / Skarmory, I usually tend to Scarf it, like Heatran, Metagross and Jirachi. When I have a potentially open slot, on a Pokemon like Heatran, Gengar or Celebi, I tend to lean towards Hidden Power Ice SOLELY because of Garchomp's existence. Not just that though. When I rate my team, the FIRST thought that comes to mind is: Does Garchomp OHKO, outspeed this and have little fear and therefore able to set up? If so, it's probably gone from my team. Note I still use Magnezone / Kingdra because both are capable of preventing Garchomp from Swords Dancing on me. Every team of mine, due solely to Garchomp, has a Choice Scarfer with an Ice move and a Steel to absorb Outrage.
3. I usually have around 3 ways minimum, whether HP Ice on ScarfTran, HP Ice on ScarfGar, Ice Shard on Weavile, Ice Beam on a bulky Water, Bronzong / Skarmory etc. etc. I emphasize minimum, because every Pokemon on my team has a way of preventing SPECIFICALLY a Garchomp sweep. This is also why I am very hesitent to use Choice item users besides Choice Scarf, as I hate the potential set up turn they grant to Garchomp.
4. Absolutely. Without ScarfChomp serving as a check against offensive DD Salamence and Dragonite, those two would run those sets much more often. Scarf Gengar (or Gengar in general, as now due to Yache's popularity I have seen Expert Belt Gengar carry HP Ice solely to lure Garchomp in on a Thunderbolt) would not carry HP Ice. The need for HP Ice on Scarf Heatran or Ice Punch on Agility / Scarf Metagross would be gone. Gyarados would certainly carry Ice Fang less. Without Garchomp, I would NEVER run Ice Beam on an Expert Belt Tyranitar, even for Hippowdon / Gliscor. Celebi and Bronzong would never run HP Ice for fear of Garchomp's supreme sweeping powers. Starmie / Swampert could run Thunderbolt / HP Electric (for Gyarados) as opposed to Ice Beam. Vaporeon could more confidently run its Wish set with the more dependable STAB move than with the centralizing Ice move. Basically...Garchomp influences everything a shitload.
5. No. Absolutely not. No way, no how.
However...I am not for banning Garchomp :P
I think unbanning Lati@s without Soul Dew (drastically reducing the viability of the Yache Set due to outspeeding and OHKOing with Dragon Pulse), unbanning Deoxys-D and Manaphy (both defensively capable of taking a hit and responding with Ice Beam) and keeping Deoxys-S in OU is more than enough to deal with the Garchomp issue :P