"Halal Meat" is a misnomer. The correct term is ZABEEHA (Muslim way of slaughtering an animal) introduced by the Imams of FIQH. Any thing including meat cannot be Halal if it is attained by Haram means.
It is always pleasing to see the Qur'an as a timeless Book. It does not prescribe any method of slaughter, leaving it open for the advancing times.
Unquestionably, slaughtering an animal through its throat must be very painful.
Stunning or any humane methods deserve our attention.
Blood? It drains out of the body in any way of slaughter. Do you ever see the Publix/McDonald meat, chicken or turkey loaded with blood?
Dedicating an animal to Allah alone, and not other entity, remains an essential part of the process.