My nickel - gravel gearing is fine. My Cervelo has a 40T front and 10/44 at the back. It's fine for 95% of everything and only leaves me slightly wanting plowing downhill (you run out of gear). Otherwise I don't sweat the fact that I probably ride it like a 6 speed instead of 12 speed.
RE: E-assist, I'm biased. If you think it'll help you get out more, go for it, if you think you'll use it as a crutch and lean on it too much and not get the exercise benefit I think you're after than avoid the temptation.