a real server/client infrastructure instead of the current P2P one would double the latency, and thus people lagging now (eg: 200ms ping, 117ms latency) would then not be able to play anymore (eg: they'd get instead a 200ms latency, equal to the ping or slightly above).
I'm not expert at all about this, but I think that a server would double/sum up the lag only if it is "on the other side" compared to both players. I'll explain it with an example:
- if player A, player B and Server are in the following locations (A-->B-->S), of course every packet from A should reach S and then come back from S to B, so the effective latency would indeed increase;
- if the locations are the following (A-->S<--B), instead, there won't be any additional delay.
Of course, there are many factors which will increase latency, among which:
- the fact itself that every packet must pass through an additional point in its route;
- A, B and S will never be alligned as they were on a straight line, so the path A-->S-->B will always be longer than A-->B, even though it won't mean a latency doubling, assuming servers are well dislocated;
- latency is not a linear function of the distance between a player and the server, as it also depends on many other factors.
Finally, I'll show a practical example. Player A and Player B are both from Italy, and their ping to TE server located in France is, respectively, 100ms and 300ms.
If the match is "run" by a dedicated server, Player B would be penalized for having a higher latency than A, seeing the ball later and thus needing a shorter reaction time. Moreover, if B has a "turtle", the match would still go on, so he would probably miss the ball.
With the current P2P system, let's say A and B would have a 250ms ping, so they are setting a 167ms delay. In this case, B, "thanks" to his connection problems, would play under conditions he's used to, since he lags in all his matches. A, instead, being used to a 117ms delay, would have a hard time adapting to the quicker aim and the smaller error margin, especially on tricky shots like volleys.
I hope all was clear, and I'm sorry about any misconception of how dedicated servers and P2P work.