The modern Hebrew Calendar, also known as the Calculated Rabbinic Hebrew Calendar or the Jewish Calendar (used by the Jews and also most of the Churches of God observing the biblical Annual Holy Days) is admittedly the most relied upon Luni-Solar Calendar in use today, because there simply seems no other better choice.
However, since it had also its own demonstrable imperfections as abundantly outlined in this article, it can still, and NEEDS to be improved upon and made accurate by instituting the needed corrections to accommodate present-day astronomical knowledge and realities extant in our modern world.