So you let Singed laugh when he flips someone...
But
still can't laugh when he kills someone with his ult?? 
But
still can't laugh when he kills someone with his ult?? 
Or say "who's the short one now?!?!?"
I think that would be more comical.
You don't realize how much Singed's laugh is core to his success. Without his laugh, he would have a 5% drop in his win rate. With this OP buff to allow him to laugh while flinging, I believe the win rate shall increase by 3.4%.... mue ha ha ha ha ha!