Now that they've chosen the foursquare name, which is synonymous with checkins, for their Yelp clone, it seems like they haven't thought out...
1. If the checkin users leave because Swarm is stupid and eliminates everything fun (mayorships, badges, reading all the tips without going to another app, seeing who else is checked in besides your friends), who is going to keep supplying them with behavioral data? Not casual users, who won't open the app and show their location at all until they're looking for a recommendations. In terms of data, casual users are takers, while the check-in users are givers.
2. Foursquare super users (their community of people who applied for edit privileges on the venue data) are probably all avid check-in users. Without them, junk venues and spam may overwhelm.
3. How do they really expect to attract enough users who want to use the new foursquare now that the app is a completely different thing? What's their differentiator from Yelp? To me it just seems like it's Yelp but with shorter reviews. Everyone who didn't use foursquare before because they hated check-ins isn't going to even know they killed check-ins and will still stay away.
I think this whole plan might have had a chance if they'd left foursquare alone as their data generator, and launched a new app with a new name for their Yelp clone. At least then they'd have a new chance to introduce themselves and try to attract the mass audience they're going for.