Whether the registrar has much power depends on the registry, usually not really (you usually can just move to a different registrar and the old registrar can n

Whether the registrar has much power depends on the registry, usually not really (you usually can just move to a different registrar and the old registrar can not legally prevent you from doing so). The hosting/email provider is obviously not a problem at all, as you can switch to a different provider at any time (just make sure to keep the domain registration and the service provider separate) if your current provider is an asshole--or you can just host your own server if you want to avoid any providers messing with your emails.