It's dead easy to say 'it should be banned'.. the bottom line is, it won't be, it makes far too much revenue in so many areas of the industry.
So campaign for change and do so with actual knowledge - so many people shouting about it know nothing, as is evidenced by this thread!
People campaigned to make fences safer to reduce falls - great, but that also made the race faster, which increased the danger.
People (rightly) made a fuss about whip use - and it is now better monitored.
You do need to understand how the whip can be used and how it can't though - it can be used to hit the horse on the shoulder, or behind the saddle - that should be (their words not mine!) to back up a request for the horse to speed up or move over that was given by a weight shift or rein aid. It can be used to wave alongside the horses face again to get him to speed up or move over.
Travelling at that speed around a course like that when you have only your weight and the reins to steer with (yes they have their legs but in the position they're in, that isn't overly effective)... it isn't wholly unreasonable to want some other way of preventing horses crashing into one another or crowding one another into the railings or wings.
But its use is closely monitored, so hitting a horse that has already responded to another aid or hasn't been given opportunity to respond, or a horse who has nothing left to give, is already clearly going to win or stands zero chance, or too many times in a row OR within the entire race IS penalised and for many amateur jockeys, that fine and that ban is a serious consideration.
Even the whips themselves are strictly controlled re weight, length and design - there is ONE supplier, they are not like any other whip you might see horse riders used, they're effectively a flexible stick, covered in foam padding down the entire length except for the bit in the riders hand. Kids in pony club wield nastier whips (and shouldn't!)
Broken legs, broken pelvises - these are injuries that many horses no matter what their job nor what they were doing at the time of injury, will not survive. Horses are big and fragile and need to be able to stand and move freely and well balanced. Attempts to save horses with limb/foot injuries have been made, with very often horrific welfare implications (and in the cases im thinking of, it was money that drove the effort to save the horse.. not welfare).
Personally I think the qualification requirements for the National should be increased, so fewer horses get in and those who do are better equipped to run.
Also specific to the GN - reduce the number of runners, 40 runners is a HUGE reason why there are so many fallers and so many accidents. Reduce it to 25.
Across the board, here is one change that would dramatically improve horses lives in racing...
The ages of ALL horses entering training (whether thats flat or NH) should be increased by 2 years, meaning flat would not start training til 3.5 rather than 18 months, and similarly upping the age they can first race. Typically jumpers aren't trained til 3/4 and raced til 4/5 anyway - but upping that age all round would make significant changes - people would breed far fewer horses if they had to hang on to them a year or two longer, horses would break down far less often and stay in racing longer and stand a better chance of a useful career later on in life.