Yet it really doesn't FORCE you to edit your team around it. Me personally, I make teams using stuff I want to use and go try it out, and if I notice that everything is weak to something, one thing, the I'd edit it to work around that. Simple. As for Megagross itself, it really can't touch my Skarm and Mandi, and it can't switch in on MegaTar sweeping. But that's just my team.Since MegaGross is the only top tier Pokémon who forces ppl to make their team basically around checking him, that argument is also invalid.
Back to the argument, it isn't the only top tier threat that makes you need to check it/counter it. What about Mega Lopunny? With Scrappy and Normal/Fighting Typing and STABs, it hits everything in the metagame for neutral damage or greater, and that's not including coverage.
Tyranitar, Heatran, Lando, Bisharp, etc. all check it and do solid damage to it, and are also very good mons outside of Megagross stuff. Physically Defensive Rotom-W is also a great counter(maybe, I know it can take some hits but not how well) and it takes nothing from Grass Knot due to being so light. Mega Scizor, and regular Scizor, another OU mon, is not hit Super effectively by any of it's attacks except HP Fire, and if you're running HP Fire just for Scizor it's doing more harm than good to your side.Sorry, i said it wrongly. What i was trying to say is that Metagross forces ppl to put many Pokémon that they usually would not use in their team only to handle him, making their team weak to MANY other threats, only because they're afraid of being crushed by only one Pokémon. That's absurd. There's no other Pokémon that do this with the teambuilding process. Not even Sableye, Altaria, Lopunny, Landorus, Keldeo, nor any other top tier mon.