Not really. SWIFT is just helps to make transaction fast. There are alternatives that include Russian and Chinese systems. And you can always use phone, fax, etc.
Disconnecting Russia from SWIFT will a) create short term hiccup in transaction clearing, b) reduce SWIFT revenues c) force Russia to switch oil/gas contracts to rouble or yuan. This in the long run is not good for euro as a reserve currency and will hurt petrodollar.