Well Balance was pretty unique in how they tried to keep the look of the old FX -even though the space battle plot could have allowed for much more- being the first TOSR episode to air and everything.
They didn't do that in TDM or Journey to Babel and many others. In most cases where they "didn't go far enough", it was pretty obviously lack of time and money more than anything. They sure would have loved to make an enhanced Vulcan soundstage for Amok Time for example.
If you're complaining about not enough courage to replace one of the connies in one friggin episode (where there was a good reason to use only connies), you should applaud them for giving us a BOP in "Enterprise incident", for sacrificing live-action material for inserting FX of Vulcan into "Amok Time", for enhancing the Eminiar 7 matte with a hovertrain etc. Those moments are more numerous than the real letdowns.
You may have wanted prolonged FX sequences, but I can understand why they didn't do that. The smooth hull on the other hand is an artistic choice and there is nothing wrong with that, really.
So if anything they were a bit shy right at the beginning with "Balance", and that one was a wasted opportunity.
But they definitely chose to get a lot more daring later on (and then a bit sloppy towards the end).
Choosing Balance of Terror as first episode was a mistake in my opinion. The Menagerie, as aired, would have been a better choice and would have pleased (most) "purists" and "progressives" alike, which the TOSR version of Balance couldn't.