I disagree.
I think suspension is the call that needs to be made.
A fullback use their knees to protect themselves. Extendinding the legso the studs of your boots hit a player approaching from front on is a continuation of his illegal sliding tactics.
In effect he actually closed the range and initiated the contact. If Kleemer hits him in the air he gets penalised. Slater nullified this by what I would deem a action outside the rules.
The Klemmer tackle would have been a result of poor timing if he put the hit on, in fact a half second or so later and he probably would have put on a perfectly timed hit in a style that actually led to a try last weekend.
By extending the leg Slater initiates the contact
Unless an opponent is actually contesting the bomb, they shouldn't be that close to the man catching the ball anyway in my opinion - tackling in mid air is the real danger here - I am still amazed a player hasn't done serious injury after getting flipped on their head. If Slater caught Klemmer 10cm lower in the chest, we wouldn't be having this conversation. Storm would have got the penalty instead.
Slater gets significant air because he throws his whole body into it, which results in his legs extending mid air to get that extra lift. I see nothing wrong with it. If we are going to start dictating how players leap for the ball we better strap ourselves in for 90% of tries being scored off kicks.