Gabdube

IMO, from a lore perspective, adding batteries of ballistas and proper siege weaponry to major fortifications would be a very good idea, but not for the reason mentioned. It wouldn't be very useful against dragons: Ballistas aren't anti-air turrets. They are long-range artillery meant to punch through reinforced targets from an elevated position, with the advantage of range, height and gravity on their side. They provide significant impact force, but they wouldn't necessarily have much more penetration than armor-piercing crossbow bolts against airborne targets, since some of the penetration power comes from gravity accelerating the heavy bolt as it "falls" downwards. Also, unlike repeater crossbows, ballistas have a very slow rate of fire, which shouldn't normally be a problem, since they are designed for long-range potshots that require time to precisely calculate anyway. But ballista bolts have a curvier trajectory because of their higher mass, which makes hitting a moving airborne target very impractical (if at all possible) even at an optimal range (~100-300m, assuming you have mad skills at eyeballing angular distance and transversal velocity), while being way too slow to maneuver and reload at close range (~20-50m). However, flying dragons can close that distance so fast (not counting evasive maneuvers) that the range advantage of ballistas is pretty much negated (while the disadvantages aren't). A whole battery of scorpios or cheiroballistras would have more success at hitting a fast-moving target before it got too close, but those were also designed to shoot at shielded infantry formations on lower ground from the top of a hill, not at a fast target moving at a higher altitude. So, the jarls wouldn't fund a large-scale (no pun intended) anti-dragon defense system if it was so impractical and skill-intensive that only one dude/dudette in the entire kingdom was a good enough shot to put it to good use against an actual dragon. And remember, it takes a while for Skyrim's elites to even aknowledge the resurgence of dragons and the coming of the Dragonborn. Everything is pretty much over when they finally get around to doing something about the dragon problem. It would be a really good idea to implement for an Empire in the middle of a civil war, though. Because Stormcloaks don't fly. ;)

Doesn't vanilla Skyrim already have barrel tub models? If not, many, many house mods feature functional barrel tubs. They generally use an invisible chair in the water to sit. Sometimes it's not even invisible. Those could be used as inspiration to make the requested mod (if it doesn't already exist).

I'm pretty sure someone has already done custom armors based on the Savior's Hide chest, with added pants and sleeves and a darker color scheme that matched the Wolf armor. I don't have time to dig through my old bookmarks, but it's probably still on the nexus.