Mine is an automatic, and serious hill climbing does, of course, cause it to shift down one gear lower - this isn't a massive high-torque V8.
Some people will complain about the 'lack of performance' with the small engine, but the gearing in the box actually gets better performance than one should expect from an engine that small. There are many vehicles with considerably larger engines that perform worse, or at least no better.
Passing at legit highway speeds is not something I've had a problem with, so long as one has enough space to accelerate. Again, we aren't talking about a large V8 - but we aren't talking about 12MPG, either.
I drive a stick. I've done a couple steep inclines. I tried the first time in 5th gear and the car couldn't handle it, I ended up downshifting to 3rd gear just so I could accelarate up the hill. I was losing speed in 5th, and the MPH didn't raise at all in 4th gear.
This was with myself and one passanger (totaling about 240 lbs) and nothing at all in the box to weigh it down, it's bair bone stock at the moment. And the incline was 15-20%.
With a manual, you'll find passing people easy in 2nd gear. 3rd gear isn't terrible when you're passing someone at 60. But 4th gear isn't going to do you much good at any speed. You have nearly no acceleration. And lets not even mention 5th gear...