SAP/Sybase replication is robust to handle start/stops of various components. So what you observed looks like an exception.
I can understand the concern/complain from a customer because single insert missing can be a big issue if it was for a huge dollar amount e.g. a big stock trade transaction.
At the same time setting up user expectation will also help. E.g. in replication system you should emphasize that primary data is "the" standard set of rows. So you can always materialize table or missing rows etc. In case of crashes you could have some sanity checks like row counts etc. built to point out exceptions. You could also use rs_subcmp utility to monitor the health of critical data between primary and replicate(s) databases.
If users/developers are ready to go extra mile you could creatively use identity column to find any gaps in case of crash. Home grown check-sums for rows in a table could be another way of maintaining accuracy.
save_interval may help. It will also increase your disk space requirements depending on what number you choose.
HTH
Avinash