It seems quite simple to get rid of ball tampering if they are really serious. No need to write hundred page reviews.
Pass the ball to the umpire as soon as it is dead. He will deliver it to the bowler. If anyone wishes to shine the ball, they can do so in front of the umpire, who can ask to check their hands if need be - when he suspects they have wiped off their sunscreen, lipbalm, pimple puss or sharpened their finger nails. Holding the ball unnecessarily long can result in a warning/penalty. This will mean the only opportunity to tamper is with the bowler as he prepares to run in. The square umpire can be watching him and typically he is being watched by the tv cameras.
Seems as simple as piss.
What else?
Regarding sledging... I presume, that if someone said something really funny that cracked me up, I would just hold up play for a minute until I composed myself again, similar to a fly annoying me as I get ready to face. Likewise, if someone pisses me off, I should just take my time. If batsmen did this, it would soon cause the fielding team to miss bowling quotas, such they it would be in their interests to shut up. yeah/nah? I have never played at anything more than e grade club level.