The frequency of the mode is a rough indicator of the ratio of stiffness to mass. This one is a bit low, but not bad. It could be that the top itself is heavy but with low stiffness, but it's more likely that the braces are a tad on the low side. Again, I've made steel strings with the ring+ mode as low as 215, and they worked OK. If the stiffness does seem low to you there are several ways you can compensate.
The scalloped braces have low stiffness at the bridge. This is what gives that profile the 'attack' and bass. The low stiffness in the middle drops the 'main top' resonant pitch which enhances the bass. It also helps the plate displace a lot of air as it moves, actually being better than way than thinning around the edge, according to Evan Davis' mathematical model. So that's good.
The problem associated with this is that the large excursion of the bridge can cause a 'wolf' note at the main air or main top pitch. Strings need to 'see' a stationary termination (or, technically, a large impedance mismatch) at the end in order to work well. Low stiffness at the bridge can cause the energy to 'leak' out of the string too fast, giving a note that's twice as loud for half as long; the good (?) old 'thuddy G'. Since impedance is a product of both stiffness and mass one way to control that is to use a heavy bridge. On my guitars, with 'tapered' bracing that's tall at the bridge, I use one in the 20-25 gram range, usually of rosewood or Morado. Martin uses a 30-35 gram ebony bridge on their scalloped braced tops for a reason. Yes, it drops the top resonant pitch, and may limit the treble response some, but it helps control that wolf.
The other main issue with scalloped bracing is low static stiffness. Over time the top can belly up under the load of the strings. What counts here is the torque of the bridge, and that's a product of the string tension and the height of the strings off the top. Setting the neck such that you get the action you want with the strings 10-11 mm off the top instead of 12-14 mm reduces the torque load proportionally. The top itself is strong enough to take the tension load, if the strings were pulling in the plane of the top; the only structural reason you need bracing at all is that the strings are up above the top.
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