I think it's the other way around... .243<.270
Now this is a rough example, but I would like to know how what you say is true in a hunting scenario.
http://www.hornady.com/store/243-Win-100-gr-InterLock-BTSP-AW/
http://www.hornady.com/store/270-Win-130-gr-InterLock-SP-AW/
338 pounds of energy is nothing to be ignored at longer range when hunting.
I know this is just one manufactures load, but if you just google it there are several comparative loads that prove the .270 to have more energy than the .243.
I will stand by my original statement saying that for longer distance hunting the .270 will be the better choice. For competition / target shooting or even varmint / predator hunting the .243 would be a better choice. Me personally would never buy either, because there are far superior cartridges on the market that fit my needs. Especially once you begin to reload.