Thanks so much for the like, I really enjoy discussions like these. I do understand that necessity. I mean imagine if I could just beam up the captain of a large ship that has its' shields down? While it happens plenty in shows, I see constant rampant abductions becoming quite an issue.
Or even worse, sudden boarding parties.
The big mechanics behind a transporter though, is you need to know where you are going. So unless you know the interior of an enemy vessel, you couldn't simply beam in I believe, or at least this would make sense; You might just beam right into the hull plating and die. One of the big things to combat that with a transporter that does not need a receiving pad, is you could require a marker, beacon, or simply for the spot to be "painted" any number of ways. Another thing you can do, is make it so it is very much one way; A pad can only beam out, not beam people in without another pad (Either a permanent, or a temporary thing, which will greatly limit it immediately to I believe non overpowering levels). A big reccomendation I would add is also to immensely shorten a one-way transport, let's say half a kilometer (0.5). Pad to Pad, I would say to permit it from orbit to ground, whatever the average distance of an atmosphere in DU is, make that the limit.
The big reason I see a transporter pad becoming kind of a big and crucial mechanic, is eventually the game will get much bigger, ships will be bigger, bases will be bigger, cities will be more intricate. While I agree with not just teleporting all over the place, It is a short range thing after all. Plus many of these limitations actually exist in the show, granted in Star Trek the transporters can go pretty far pretty quick.
As for limited use, I'm not sure. I think there shouldn't ever be such limits imposed; Remember, we're moving within just half a kilometer of the pad; Not across the galaxy to meet up with friends. I also just simply do not see this really breaking any war mechanics, or ruining immersion as I stated previously (Let's be real, we're going to see giant yellow duck and dick ships).
Another bonus to the system is just how easy it will be to implement in the future (not at release). We'll have stargates, which I hope will be unlimited use, as I'd love to go exploring; Which will already form a level of point to point teleportation. So it's really just an adaptation of the same mechanic. At least that is my assumption.
Anyways, personally I would love to see it; The only last thing I could state; Like a revival chamber, what if they where personal or organization use only? That would solve most issues I think.
I just imagine having a flagship to doorless HQ transport made possible. Anyways I am off to bed, thank you for your thoughts!