You are comparing apples and oranges. The front wheel of your tricycle is providing traction and steering.The front wheel of a bicycle however, provides steering and balance, together with the weight of the rider. If the rider overbalances to the left, you turn the front wheel to the left, and if overbalances to the right, you turn the front wheel to the right. You of course do these minor course correction unconsciously. If the front wheel has too much mass, the front wheel would have too much inertia and these minor course corrections would be delayed with possible consequences. The front wheel does not just turn for the purposed of turning, but as I said is required for balance, but at what added mass to the front wheel does it start to interfere? Baskets and panniers are not unheard of attached to the front wheel, but are rather uncommon. I still feel purposely designing a front wheel on a bicycle to be heavy is a bad design.
With regards to your tricycle, increasing the weight to the front to increase traction will compromise stability. A tricycle is stable because more of the weight is balanced on the back wheels, moving it forward will increase the chances of pitching forward into a spill.