I agree with FullWings that an electronic solution is certainly possible. But given airlines unwillingness to pay for stuff that might have prevented accidents (as suggested by Boeing now including things that were options previously in the 737 Max) it would probably only work if it was mandatory. Light aircraft rules of thumb (speed at halfway point for example) are great with full thrust takeoffs and familiar airfields. On the Airbus/Boeing aircraft I flew I don't think you can eyeball it and the incidents I heard about were mainly flap setting issues e.g. people setting flaps 1 with flaps 5 speeds. With experience you should spot on medium jets if something is strange about the V speeds, but much harder to spot acceleration problems on unfamiliar runways with varying met conditions.