Ideally, Mr.Bauman is right (as he often is when talking about a perfect world that doesn't exist). The proper place to hold a train is usually in a station. However, in the case of holding the R, for example, there is a V train somewhere behind it that has to stop at Queens Plaza and then go somplace that the R isn't going (that is to say, via 53rd Street).
The maximum amount of time it should be necessary to hold an R, N or W to avoid a merging conflict is 1 minute. Both the R and V are running 9 tph for a combined headway of 3 1/3 minutes. There should never be a problem with delaying following V at Queens Plaza. Similarly with the following headways at QBP will permit holding the train in the station without delaying the folower.
Is there room for improvement? Probably, but it would most likely require resources that the operating divisions do not have.
Increasing running time between stations wastes resources. Resolving merging conflicts by holding trains in stations only partially mitigates this waste. However, designing schedules without merging conflicts does not require additional material resources.