Building fortifications is fine, especially for arty. But once started, it can get a bit carried away. I remember some Friday linebattles many months ago where this was the case, it became fort wars of attrition. This is why I like the idea of a time limit and build points limit. Just enough points to give the arty a reasonable defense against some cav or artillery shots, but not enough to create The Alamo and encourage the entire team to camp there. I didn't really see this last night at all, maybe a little bit from us if anything. But I've seen it at its worst in other battles.
And Crawford has a point, while it's nice you guys want to protect your arty as best you can, saving an entire line as large as yours to do so is overkill. Depriving the front line of your firepower is in general a bad idea. You artillery has guards for a reason, to stave off cavalry until someone else can make it back or they break off. Defending artillery that vehemently with an extra line in reserve rarely goes well in the long run.