Does conjunction between two planets make it stronger and the effects better more prominent than square/opposi?

The conjunction blends two planetary energies together. But sometimes, you can have two planets that can cause disaster like Mars / Saturn (hot and cold) in conjunction. The effects are more prominent in squares because THESE are the asepcts that build character. You cannot ignore them. Squares are the most powerful aspects in any chart followed by the opposition. As i pointed out in other answers, if you work with your square aspects in a constructive manner, they will be very very rewarding. If you ignore them, you are letting the square aspect be destructive and negative.