1) You can only exit from the point you came in at. The meeting place is not a train hub where you can hop between places.
2) Some of the points of access are known and some aren't. Some have been forgotten over time and some shift about in location.
3) The access points are potentially easy to stumble upon but not always readily noticeable or super obvious. One minute you're there and the next you could have walked into one. For the truly observant ones there would be a faint environmental fluctuation to them or a very, very slight magical hum for the more sensitive characters to notice.
4) As the portals age they can cause glitches. Sometimes this means they don't work entirely, or they may send a user flying across the map to somewhere entirely different that is neither the meeting place nor their original starting destination. The glitches can be extremely minor to extremely dangerous. There is no telling what may happen should a character end up in a glitched portal.
That being said, yes you can create a magical sort of IT character to be able to repair access points.
5) The meeting place has always existed and nowhere knows where it started only that it works. Mages over time have been able to use certain special magics to maintain the existence of the Meeting Place however, they have been completely unsuccessful in duplicating its effects. It has been deemed by the vast majority to be far too dangerous and too much of a risk to continue such veins of research as attempts have resulted in forever deactivated portals.
