> Games that don't optimize and use more data on the wire actually feel more responsive than games that are wasteful with data.

I re-read this three times and still can't parse what you're trying to say. Mind clarifying?

Flush on full means the data is only sent when the buffer is full. If the buffer is large and you have an optimized game that minimizes the amount of data sent then the buffer takes longer to fill up and packets are sent less often.

Older games that send more data may get quicker response if your throughput is high but your packets are large

If the game doesn't optimize down the total data it sends, then it's constantly filling the buffers, so there's no waiting for buffers to fill which can reduce ping times.

I think op means games that aren't wasteful, i.e. they send a smaller amount of information with less redundance.