I think your point is valid and important, especially considering the average user. However in my experience it worked surprisingly well with a long word based

I think your point is valid and important, especially considering the average user. However in my experience it worked surprisingly well with a long word based master password. Since I only needed to remember 1 password that I then used daily it was not that difficult. And typing it was quick since it was all lowercase which most keyboards are optimized for. However the issue came when I started using my password vault on my phone and tablet. I was way too slow at typing on them. I now have a 22 character password which takes the same time for me to type on a keyboard, maybe a bit slower, but is faster on my phone though still annoyingly slow. As for 70 bits password, it might be enough, but you need a lot of iterations (2^58) if you want to completely make up for the lost security margin. Which will also be unusably slow in practice.