But that was the problem. ENT, stylistically, structurally, and writing-wise, really wasn't all that different from Voyager which came before it.
I think whether or not Ent was "stylistically, structurally, and writing-wise", too similar to Voy and TNG is debatable, but even if it is true, just because the shows are set in different centuries in the Trek-verse, it does not necessarily follow that the shows must be structured, written, and stylized in different ways. The differences between the time periods in which the shows are set can be emphisized while using similar writing techniques.
This is assuming of course that I understand your meaning of "stylistically, structurally, and writing-wise". But regardless, I'de love to see some examples from both shows that illustrate what you mean by this.