The only change I've made to the core rules in my current Savage Worlds campaign, besides using the aforementioned "Hordes of Extras" setting rule, is that I let a player add additional extra dice to their damage roll if they make an absurdly high attack roll. I feel like if you roll a 64 on your attack, which has happened at least twice in my current campaign, there should be a bigger effect than just adding +1 d6. I haven't codified how many dice or what type of dice to add- it's just whatever I feel is appropriate in the moment.
ETA: also, the Action Deck from the Adventure Edition boxed set comes with an extra Joker, which I leave in.
ETA: also, the Action Deck from the Adventure Edition boxed set comes with an extra Joker, which I leave in.