There's a fine line between "synergy" and "crippled if CDs are desynced". Synergy is like Internal Release increasing the relative value of a double-Bootshine rotational string back in SB or decreasing it in HW to a certain breakpoint, adjusting your optimal choices but not to a point that one need be held for the other. Synergy is 6SS finally being usable, if only at the end of a damage CD's duration and when mindful of sync elsewhere (that is, if MNK still had some way of adjusting its sync, which it hasn't since 6SS's release with ShB). Synergy is being able to use TK when able to quickly generate it back, though at cost to another rotational possibility and not so strong (such as due to, say, a bug making its damage 39%-45% higher than stated) as to be obligatory. Anything past that is simply costing two buttons for a single combined action, dependence more so than synergy.
Yes, Monk lacks synergy. But let's be careful not to fall back on such bottom-of-the-barrel examples as the "synergy" of DWaD and Assassinate, for example, when we try to fill that lack. Assassinate is literal bloat. It could merely be apm bloat, par for NIN's former high-speed identity, and that'd be fine so long as there's nothing that other double-weave that would be obligatory in that same GCD (and at present, there isn't, so by all means). Using two buttons, however, just to effectively DWaD twice is hardly design worth imitating.
Right now, Monk has a few too many underpowered tools in much the same vein as pre-buff Meisui (a button previously devoted entirely to a potential mistake -- if someone forgot to instead use Fuma-Katon-Doton instead of a Fuma-Raiton-Suiton when TA is already on cooldown and the effect will not cover all 3 hits), but it's had far closer misses much more worth imitating just within its last two expansions than it'd see from, say, 5.1 NIN. It needs synergies, not bloat, not over-dependence, not skills used just to unlock another skill, and certainly doesn't need its apm crippled. It can afford to be a bit esoteric, a bit eclectic; it need only be synergetic, sensible in the context of its own skills, and fun.