Last time I played this, it was still an incest game. Just to confirm, its NOT anymore, somehow, magically, right?
Is this still a clunky boring open worlder with generic animations?
Your "step-sis" is still one of at least 8 or so locals you get to 'date' - not counting NPCs on the side or adventures. You get to have one lucky character move in with you, who you wish to get preggo (embiggen - no birthing). It cannot be undone if you change your mind (so save your game). If you don't want the preggo fetish, there's no need for "your" house at this point of the story. If a characters moves in and they are still receiving any dating story progression updates, I suspect it could bug/prevent that toon's story progression. Make plenty of saves.
Is it still the same open world game ... there have been improvements. Depending on when you last played will make those improvements seem that much more. Some of the minigames haven't changed (pizza run, bike race, space boss bullet hell). Considering this is a few indie devs and not a studio (like Mad Mind), do not expect Succubus-level game refinements & expansion. The Devs have their development priorities but fewer resources.
If you want a polished, final game, MB is not that - yet. It's enjoying the process of a game's evolution or occasional new game play -- kind of why I went with the Itch purchase vs Patreon to support them. A one time purchase with legit updates over a few months having 3 new versions of game play bundled together. Having tried a few 3D game here (my preferred games), it's one of the better ones. Plus it has a highly complete customization of nearly every toon in the game (which you can back up too) -- which is super rare.