I've seen this as well. But I take it as my reminder to literally not be so stressed out about joining these firms. Don't get me wrong, have your goals and aspirations as we all do, and commercial law is a very good platform for career development, networking, travel etc, but at the end of the day, it's a job, so don't spoil your health over it. Your 2-year TC could just be a springboard for you to go on to do something much more valuable for the world lol. We need more socially conscious people rather than more secondary PE funds.
This is so important as well. Meet firms, even if its for 5 minutes at a packed networking event, you will learn a lot from the way they interact with candidates. Although, I have found that US firm trainees tend to be the most disillusioned. Really nice firms I've recently met are WFW,
Bristows,
Bird & Bird,
Taylor Wessing, OC.