FrogReaver
The most respectful and polite poster ever
it is a power balance issue, I am just worried the fifth level thing would shoot past the mark...In effect, through 4th level, 95% of my attacks look just like a normal monk weapon attack plus unarmed strike. Periodically I expend one of my 4 ki points to do flurry of blows in addition to the usual attack sequence.
The thing that seemed unbalanced to my DM, I am speculating, is that the fighter character, when expending superiority die (forgive me, just learing the 5e system so some of this be off) they can end up with rounds where they are delivering easily 20 or more points of damage while the monk character, spending a ki point maxes out around 16 if the normal unarmed strike is removed in order to spend that ki point.
A well played open hands monk can easily cause much more damage than a well played fighter using two weapons (at least until the fighter reaches level 11+). Chance to hit matters for damage. Open hand monks excel at proning enemies and thus granting themselves and other melee allies advantage. Monks are beast and don't really need additional help.
That said monks struggle to keep up with what feats can grant other classes for damage. In such a scenario you just fall back more on control and buffing your allies (stunning strike and proning enemies).