changing the gameplay too often is, of course, a bad practice.
i was more refering to building up the game ecosystem by adding new features and functionalities both online AND offline.
for example add periodically singleplayer mini-campaigns that unlock you something, interactive in-game tutorials, hell… even re-enactments of famous matches from Evo where you are given a certain situation and you have to win from there (like SnakeEyes’s comeback vs Xian). this would engage the more casual crowd that doesn’t really like going online and be super competitive.