Sliding is ridiculous.
Ridiculous because of how bizarre it is and unrealistic it is.
Yes, I know realism isn't _necessarily_ more important than gameplay, but it is when the resultant gameplay is so stupid.
If it must be in game, no way should people be allowed to shoot while sliding. They should also be inaccurate for a bit after sliding.
They should also have a good chance of a 'fumbled' slide on uneven ground that leaves them flat on their face.
The slide makes the game feel childish. Not something a soldier would ever do unless the situation was perfect and they were utterly desperate for cover.
The slide-to-kill is a silly meme from shooters that don't care how silly they look.