IMO, reducing thrust for takeoff reduces safety in that you attain less margin for error than if thrust is maintained at a higher level. That is balanced with the lesser probability of catastrophic engine failure at reduced thrust. However, reducing thrust from FULL T/O thrust may increase safety overall, since engines are not designed to maintain full thrust for very long, and long-term wear is definitely increased.
However, especially when using deep derate + assumed temp reductions (e.g., 25% reduction) for takeoff, I see NO value in reducing thrust further for climb. This is supported by the fact that in the GE CF-6 or GenX engine on the 744/748, CLB (which is essentially equal to Max Continuous) or CLB1 thrust is significantly higher than T/O thrust when using max reduction.
I would like to see the allowable T/O thrust reduction be limited to no less than normal CLB2 derated thrust.