Elena was also brought back to life through that magic sacrifice Bonnie did that linked John Gilbert's (her biological father) life force to Elena so when he died she came back to life but I don't think she never saw any ghosts because of that nor will Katherine.
I'm not sure about the rules exactly but the magic has to be tainted for the consquences to happen. The gilbert rings revive you some time after you've died and I don't think Alaric ever saw any ghosts (except for Esther when she was preparing him) either and Jeremy didn't see any up until Bonnie revived him specifically with her hands and just after he died.
I think something is consistent and that's when you use a direct revive spell the victim in question will suffer some consequences like become a medium because direct spells require too much energy. A witch that utilize different power sources than themselves (expression) or their own magic (spirit magic?) can conjure more powerful magic like using other elements like celestial events, fire, water, other witches (channeling), sun, trees and possibly other things we don't know about.
Considering love and death are strong themes in this show I suspect those can be used as well.