Last I checked, in-game Pokémon has a per-turn timer or something (hell, we have an optional one already) that doesn't necessitate direct rules about slow play, plus there is a system to determine a winner if the clock runs out. The latter enables time stalling as a potentially legitimate strategy.
I don't think time stalling SHOULD be enabled at a legitimate strategy is the thing. Sometimes games go to time, it happens, but when possible games should be allowed to be played out to their natural conclusions.