Because we don't feel it's ready yet.
The realm has to support itself in some way.
Yes to the first. It can be done server-side. To the second, RDF will stay as it is for the time being. Whether or not it will change in the future remains to be seen. The point behind having RDF disabled is force players to organize their efforts via LFG channels and summoning stones much like was required in the early days of WotLK and in TBC and late Vanilla. We don't want people just cruising through leveling with the RDF feature right away.
To your third question, yes of course. To your fourth question, it will be a pvp realm as far as I know. This will encourage further action between the two factions as they level up.