PVP Matchmaking- Why only 5 at a Time?

Is it not possible for PVP teams to be divided after all 10 players are found? This seems common to most other pvp games/game modes.
Right now, it’s kind of frustrating when your team of 5 is formed, all solo, highest rank is 20, then you wait for a few minutes only to have the other team finally to be found and revealed to contain two parties with no player lower than 20 . . . It would have been so simple to have those parties and solo players split much more evenly had all 10 been found at once . . .
This seems to be a fairly common occurrence as well, unfortunately, and leads to many games involving quitters right from the get-go (and I can’t really blame them, as this almost always results in a severe throttling).
I realize not much can be done if an entire party of 5 rolls up, but I understand they’re already prioritized to match up against other parties, which is good.
I just wish the matchmaking for the rest of the solos/smaller parties was handled better.

Don’t know about the mechanics, but you really should ignore the player rank - it means relatively little, and is not actually used in match-making. (This is explained in the developer Twitter AMA transcribed on to Reddit that has been linked a few times on the forum) Disconnects are probably a bigger problem…

Well, that’s good to know.
The problem of 5 solos vs a team of 2 parties still persists, though, and seems as though it may be mitigated by finding all 10 players before splitting the teams.
Not sure why this isn’t the case. Perhaps there is a very good reason for it, but it just seems like such a common thing to most other pvp games that I don’t understand why it’s implemented the way it is here.

Why not just plan for a match here, and set up in private PVP? Not trying to be rude, I’m just thinking that would be a good fix atm. Also, please tell me if that’s impossible, I’ve never ran a private PVP match before.

That’s not a reasonable solution at all. Not only does that take away the ability to get challenges done, it takes a significant amount of time. This is simply an issue with matchmaking. There should not have to be workarounds.