I agree the spirit of the LBW rule was to stop batsmen deliberately blocking the stumps with their pads, if I was an umpire it would have to be very plumb for me to give one and I doubt I would if the batsman was genuinely offering a shot. With the DRS system they are way over analysing and its against the original intention of the rule.

Sport does not need to be laser precise for most its just about having fun. I played A-Grade local tennis and the vast majority of players would accept calls by your opponent at the other end, you had the odd cheats but that was rare they respected the nature of the sport and often bad calls balanced out. I used to serve at well over 200 kph and to be honest I could judge the direction but the precise spot where the serve landed is hard to see from the servers end and often problematic for a receiver when a high speed ball comes through .... often whether a serve was an ace was guess work. As a receiver if the trajectory looked about right  I would concede an ace.