You're forgetting something. Ok, so hypothetically let's say one of them were to step down - one of the admin, mind you. Said replacement isn't guaranteed admin access, not with the current unreliability of the webmasters.
Re, other options: Whatsapp blows ass on Windows, as it still uses the outmoded method of retrieving messages from your phone's Whatsapp via Bluetooth, not to mention its accessibility is a bit unreliable on pc. Telegram is better. But as has been said, communication medium isn't the only problem at bay here.