Believe what you will, but the ability to power objects opens up many new doors in what can be made: lighting, seal-able doors, timers, etc. Sounds fairly redstone-esque, but that kind of option to have powered objects elevates creativity in ways that static terrain just cannot hope to achieve.
Additionally, what about magnetism? Imagine structures built upside-down only navigable if you have magnetic boots or plates to keep you attached to the blocks?
Magnetism could also allow logical floating structures, or accelerating tracks for movement!
Electricity and Magnetism options in crafting would be amazing and very expansive for learning, imo.
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