There is a reason that car rentals don't like that road. It's still pretty rough on vehicles and the one way thing is a real time /expensive proposition. Motor home rentals here in BC charge extra just if you go up there. Pavement is still a little skimpy in places (like none) and it's still can be a long way between services . The route is well worth the effort if you'd like seeing the North close up. Varied is just a word until you put it infront of what's available enroute. I think hwy#97 North off of #16 just west of Hazelton would be my choice instead of via Dawson Creek.
I have done the Alaska highway route and I have done the other route via Kitwanga. The Alaska highway has been upgraded a whole lot over the last few years - it is getting very smooth these days. They have straightened out the highway from a very narrow, crude and rough road to one that is quite navigable. There is road construction in some places but overall, the road is quite good and it is paved all the way. I like the other route via highway 16, but it is still quite narrow, rough in places, and very remote. Beautiful scenery, though - another drawback is the gas prices are quite atrocious. The remoteness and the cost of gasoline or any car problems make it a little risky. You want to make sure your car is in good condition. About the car rental - can''t help you there because we drove our own vehicle both times.
UPDATE: My comments remain the same. Spoke to chap yesterday who had just finish the trip (return) Said and I quote "Not like it used to be..... only lost one windshield this trip" So as Evergrn says it is getting better.