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I imagine a coin where blockreward gets reduced by 10% a year instead of dramatic halvings. Blocksize scaling is built in at predictable intervals. Mining is done on the the more secure SHA512 or something more quantum computer resistant. It may have a full Turing-compliant scripting language for smart contracts, etc.
You mean... bitcoin done right... I am afraid it is too late for the old bitcoin we are trading, too complicated to change... better start anew...