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.
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.