The current system makes it likely a player who reaches a high arena score might just stop playing and park there to win the season. The suggested modification would mean that same player could continue playing without jeopardizing that high score, while also striving for an even better one, while also continuing to incentivize everyone not in first place to keep grinding toward that top spot.
As noted, we won't know for sure what the result would be unless it is tried.
As noted, we won't know for sure what the result would be unless it is tried.