As I said, to consider any variant of chess where the king can be captured, the essential first step is to change the rules so that it is possible to reach a position where the king can be captured. The natural way to do this is to remove the rule that moves doing this illegal (this rule primarily protecting players against the most heinous of errors, to leave the king in mortal danger).
(Aside: it used to be traditional not only to say "check" to warn a player of a threat to their king, but also "gardez" warning of an attack on the queen. )
But to get a variant where the K can be captured, it's only necessary to extend the game by one move so that if a check can't be escaped from, you make another move and your K is captured next move. To get rid of most cases of stalemate, you have to allow the K to move into check. Why, if it removes an interesting dimension from the game. In what way is it desirable?
It's not.
But a second way would be to say that making a move is mandatory unless you don't have a legal move. That way the king doesn't have to move into check.
Not altogether on topic. It's been discussed on other threads.
As a non-mathematical aside, I have always considered checkmate, as it is defined, an elegant way for the game to end.