Realm skills… where to start?

I’ve been ignoring realm skills and am wondering where to start? What have people been doing so far? Start with your top team? I haven’t the slightest idea why some heroes have realm skills and some don’t, and I’ve been wondering whether the choices will make some kind of difference down the road when they finish rolling out whatever grand plans they have for realm PVP or whatever else…

I’d happily take advice, even if it’s “you probably couldn’t go wrong with doing XXX”…