So unless an attacker can completely disconnect you from everybody else who's interested in a particular IPNS address (and in that case you're lost anyway), they can't hoodwink you into going back to an old version.
The traditional internet solves the problem of not being able to trust your internet connection (say, in a coffee shop) with public key infrastructure so that the most a rogue internet provider can do is DoS you (they can't get a certificate for google.com and TLS is protected against replay attacks), so this sounds like a downgrade in actual security.
The corresponding attack against IPNS would be if the attacker could make your perspective of the world go backwards, and that is prevented by the sequence number.