I certainly defer to those with type specific knowledge, as I have not flown, nor maintained a DR-400 (I'm not aware that there are any in Canada). If no toe brakes, then yes brake steering, and differential setting becomes more critical. Some early PA-28's I have flown, and the Tiger Moths have brake levers, rather than toe brakes. I think that the Tiger Moths I flew had a differential brake set up, but the Moth on wheels did not seem to have much noticeable function in this regard, and the other Moth was on skis, so it was moot.
Improperly serviced landing gear will introduce problems. That said, at faster speeds on the runway (let's say 30MPH and faster for many types), the rudder is really doing the work to steer, rather than the nosewheel. If the nosewheel is held light (or off) directional control can be maintained with the rudder alone. If the nose tire is in contact with the runway lightly, it will just scrub a little.
When I train, I teach this by lifting either the nosewheel or tailwheel off the surface, and demonstrating that control can be maintained. No, one should not fly unairworthy aircraft, get it fixed! But, don't give up attempts to maintain control either, use what you've got, including ailerons, in a crosswind. If you're really worried, choose a wet grass runway for arrival; story:
I was once asked at the last minute to ferry a 172 from a grass runway, where a junior mechanic had performed maintenance, back to the main base for the aircraft (which had one grass runway. I did the walk around, everything seemed to be where it should be, and tightened, so I started it up, and taxiied out to the runway. It was not taxiing well, but with steering, brake and rudder effect, I could taxi as needed. While backtracking, I noticed that the left mainwheel was not turning, just sliding on the wet grass. I thought about taking to plane back, and undoing everyone's plans for the day. But, I could taxi with no problem, so takeoff should be okay. It was, and I landed with no difficulty on the grass runway at the destination. I stopped short of the paved apron, and shut down. The boss asked why I'd parked it there. I told him to have the mechanic taxi it in, and he'd figure it out. The mechanic had reassembled the left brake incorrectly, and the brake pads were bolted hard to the disc - he had not checked his work. Okay, one more landing gear maintenance story;
I flew the perfectly fine 152 for it's annual inspection. Upon completion, I flew the post maintenance check flight. It did not want to taxi straight. When I took off, the weight came off the nosewheel, and the rudder pedal when slack. I could pick it back with my toe, and it just flopped around. I landed back, paying very careful attention to keeping it straight on the runway. I taxiied back the hangar, and explained to the mechanic that I was not satisfied. He was unconvinced. I told hi to get in, and flew it again. Once in the air, with a flopping rudder pedal, he could not dispute my objection. 'Turns out that the two nosewheel steering pushrods, which contain springs, are different lengths L for R, to account for the rudder bar offset under the floor. He'd installed them L for R. Once the weight came off the nosewheel, and it centered on the cam, all the springs in the system started fighting each other, and the rudder pedal function was lost on one side, as the springs took up what should have been rudder cable tension. The maintaner had not checked his work. A few hours of remaintenance later, and it flew just fine!
Good maintenance is worth the trouble!