We hiked and camped at Joffre Lakes this past weekend August 12 - 14, 2016, and was it ever busy. I hadn't hiked the trail for about 10 years and I don't think I've ever seen so many people on one trail. We were lucky to get there really early in the morning, so we got a parking spot in the main parking lot but there were cars in the overflow lot and cars parked along the highway too.
The improvements made to the trail have definitely made it more accessible as the old boulder field that you had to hike through is no longer an issue. I'd almost say this hike is fairly easy now.
Despite all the people, the views at the top are amazing. You can hike up to the glacier for a view of all 3 lakes but it's a steep hike and unmarked trail.