Manual exposure is not difficult but you need to invest some time in learning. I don't use the meters in my K-5s. If they didn't work, I'd never know. I do use a handheld meter to measure incident light but more and more, I guesstimate and adjust with the histogram aka "the modern Polaroid". Its is easier with a lot of experience and constant use. Also have a flash meter but that's a different kettle of fish.
If you learn the Sunny 16 Rule as an anchor point and understand it's based on an EV of 15, it's easy to mentally calculate the exposure. Here is a free, detailed explanation.
Ultimate Exposure Computer
Manual focus is a different issue. There was a reason for the phrase "f8 and be there" Knowing depth of field and pre focussing made a lot of photojournalist work possible. The new digital cameras do give you a focus confirmation but there is also use for split screen prisms. A lot of this depends on what you're shooting.