I hiked Whitney on July 22nd. I've hiked Whitney 3 times before, and the trail did not seem different to me. I'm not sure what reroute the original poster is talking about. They might have ended up cutting across to the Mountaineers Route trail.
As a side note, the camp that the original poster is referring to is often called "Trail Camp". Mt. Whitney does not have a "Base Camp".
If you're concerned about altitude, a much better idea is to do more day hikes at altitude before attempting to summit. Onion Valley and Horseshoe Meadow are both good places to check out. There is also the Meysan Lakes trail out of the Portal. I'm not a huge fan of that one, because it is hot, exposed, and steep. Note that camping at Trail Camp will only help you with altitude sickness if you don't feel the symptoms at 12000 ft.
