How can I lower the I/O pause if 20-35 seconds is just too high?

With all of the information above, it is pretty easy at this point to make an educated decision on how to lower the overall pause in I/O when a link (or multiple links) are unexpectedly lost.

In speaking specifically to VMware ESXi, the options are fairly limited as 1 of the 3 configurable values are already set to their minimum by default.

 Name                  Current     Default     Min  Max       Settable  Inherit
 --------------------  ----------  ----------  ---  --------  --------  -------
 NoopOutInterval       15          15          1    60            true    false
 NoopOutTimeout        10          10          10   30            true     true
 RecoveryTimeout       10          10          1    120           true     true

Since we know that the NoopOutTimeout value is already set to the lowest available value (10 seconds) that means we have two options we can modify to lower the length of time which I/O is paused (NoopOutInterval & RecoveryTime).

Modifying the two remaining values will assist in your effort to lower failover times and get I/O back up and running quicker.