The best part about Foursquare for me was a personal diary of things I did, the ability to share and gamify that diary, and only as a headfake, get location info. Swarm, not so much. They should have just made two apps -- one, the present day Foursquare, and another for Foursquare check-ins. They didn't have to create another brand. See how FB split itself into multiple apps.
Also, they killed the diary, the mayorships, the accomplishments. It's very hard to trust them with even an icon space on my phone anymore. Foursquare wanted a bigger toy, it threw what it had under the bus, and it wound up with neither.