It was rather common practice to mount the undercarriage this way at the time, just look at designs in the 1930s... a wider undercarriage meant a lot more load on the wing, a heavier design. Most designers opted for performance. Mounting the undercarriage on the fuselage had a lot of advantages - fast wing change, easy transport, and eventually, the fuselage could bear more transmitted load than the wings. Never underestimate operational factors ! One factory pilot I know took off a 109 to battle on his own - damage to wing in combat. After he landed it was changed within a few hours and he flew back home on that afternoon! That 109 was operational on the next morning because of that. If they would have to disassamble to u/c, support the plane etc. it would take a lot more.
Actually the only downplay was the narrow track width, which would leave with poorer ground traction. I guess the Bf 108 was also a serious reason, as the 109 was based on it almost directly. Hardly something to be ashamed of, as the 108 re-entered production post-war, it was so nice. However the guy is wrong in that it was never improved, the wheel track was slightly increased, and much larger tires were used later. I doubt anyone who driven a car with just slighly larger tires would argue how much difference it can make in handling...
