One of our main goals was to ensure that there is minimal side-effects of our changes : since we are unable to test it in all modes unfortunately : mesos, windows, etc.
Bumping from 10 to 30 means it takes more time to recover in case the slave is "hung".

The 10 seconds write timeout was causing issues particularly before the ConnectionManager and Connection changes. I really do not like fudging with timeouts since they are (usually) just procrastinating the problem instead of fixing it - but in a yarn cluster, given mulch-tennency, 10 was a bit strict at times (particularly with gc pauses when worker is in heavy load - proc or IO).