I can't imagine not being able to save a game. I imagine if you couldn't, people would leave their consoles on all the time, which I don't know is good for them or not( I worry about leaving my Wii system on for too long) it's just such a convenient feature, because nobody can play all the time. Also about difficulty, I consider myself a very casual gamer, so games definately don't need to be hard to be enjoyable, it should be easy enough for everyone to be able to enjoy, I play Paper Mario 64 occasionally and it's not a hard game but some parts are a bit challenging, I enjoy that kind of game. If you want super hard games, buy those. If not, buy easy games, simple as that.
About modes, you should be able to play harder difficulty modes if you want, but it shouldn't be required.