No. A lamp made for an incandescent bulb has a parabolic reflector that directs the light where you want it. if you replace that bulb with a different light source, even if it's more powerful (which an LED probably is), if the light source is not at the focal point of the reflector you will get less light where you want it.
I agree with your reason that parabolic reflectors and LED bulbs don't work well together. I'm asking you to clarify your point about LEDs optimized for 3-watt input. It appears that you are saying that the 1.8-watt output may be insufficient. Am I correct?