I had someone ask me why I consider some VN battle scenes to be good and others to be low quality just the other day, and I thought I would address this here.  

First, I should state that while visuals definitely have an effect on the quality of a battle scene, the quality of visuals is less than 15% of the reasons why I pick one VN's battle scenes over another's.  The considerations when it comes to visuals are raw quality (artist skill, detail, etc), number of combat-related CGs and sprites, and the quality of the visual effects.

More important (roughly 25% of the whole) is music and sound effects.  It is quite possible to turn a VN whose visuals are mediocre and writing are good into a masterpiece based solely on how the BGMs and sound effects are used.  I've seen it happen (Devils Devel Concept being a prime example), and I can honestly say that this aspect almost always trumps visuals when it comes to determining the quality of a given battle scene.

Another 25% comes from context and presentation.  I split this evenly because these two factors tend to be inter-dependent in battle scenes.  Without the context, you can't tell whether you should care, and presentation (the art of bringing writing, sound, and visuals together to create a collaborative effect on the reader) quality can dramatically alter how you see the battle.

The last 35% is all writing.  My prejudice would have put it at 50%, but realistically, in a VN, writing is at the very least 35% of what determines the quality of a battle scene.  The very simple reason is that making a battle scene interesting requires an eye for detail, for stringing descriptions of character actions, emotions, and words into a cohesive whole.  There are plenty of writers outside of the VN industry who only do this well and literally are incapable of 'peaceful writing'.  That is because what is demanded of writing during a battle scene is fundamentally different from what is demanded outside of battle scenes.  To be blunt, most VN writers have no idea of how to write a battle scene, which is why the good ones stand out so much.  'Tom blasted magic sword at Dave, Dave took it on his shield with a grunt' is about as far as it goes with most VN battle scenes... and that is fairly horrid, since there is no sense of what is actually going on in that exchange. 

It isn't uncommon for VN makers with unskilled writers to simply substitute visual and sound effects for descriptions of the battle simply because the writer can only handle dialogue and minimal or copy-paste action lines.  However, this results in amazingly boring scenes, since there is usually almost no variation in visual or sound effects from scene to scene, action to action.  This means that they are essentially using a square block for a round peg.  I don't know how many third-rate battle scenes I've fallen asleep to over the years...  

Anyway, ideally, a good battle scene should have all the elements come together in one cohesive whole.  However, in practice, that almost never happens.  About the only companies that have ever managed to do that consistently are Nitroplus, Light, and Propeller... and we all know what happened to Propeller and (more recently) Light.