I can't promise that I'll fix all the vanilla jank, especially the clipping into walls with items (for reference, you can glitch through ANY wall, no matter how thick, with nothing but a wooden hammer, in pure vanilla Terraria).
But I will definitely try to fix what I can!

Just going to tack on some points you made in the main comments section too, to help keep a bit of a TODO list for myself:

- Pedestals still let you clip through 1 block walls when running at them.
- Small pedestals complain that they're obstructed when next to walls on the left.
- Large pedestals do the same if a block is above them on the left side.

Finch is a silly bird and I will not fix it, that would require changing the bird's AI which I am hella not touching right now.

edit: also not fixing blaster cannon. It's a minor, hand-related visual issue and I have bigger fish to fry right now. This kind of problem tends to be more involved than expected to fix, too (AKA it takes a lot of time).

edit 2: Apparently you can clip through walls into vanilla beds as a dragon, too. It seems Terraria's line of sight check gets a little wonky with non-standard hitboxes. I'm going to pass this one off for now.

Terraria's 100% got some jank to it, probably even more so with a mod like this. But I imagine that, if this dev doesn't completely smooth it out (which they don't entirely have to, at least not right now. The framework they've laid is incredibly impressive, even more so for what seems like mostly a 1 man coding team.), then someone else will in the future.

Aight, I'm fixing a few things but there's a LOT of stuff here's that's vanilla jank I'm just gonna have to say "Not going to fix, just avoid it", which I don't like but it'd be a truckload of effort to try and fix all these very specific things.
And yes, I'm just one guy doing the dev for this, with some support on the armour art side atm :)

Stuff I did try to fix:
- Pedestals should be a bit less glitchy. Still some edge cases, but it should be at least generous instead of selfish (no more 'obstructed bed' when small pedestals are next to a wall, stuff like that). I can't really find a sane way to fix the clipping through walls or some specific arrangements where you can/can't hop on a pedestal, yet the game thinks the opposite is true in terms of obstruction status.
- I'm adding some special offsets for fishing lines so they can get into the right spot. I can't promise modded fishing line compatibility right now though.
- Golf Clubs shouldn't break the dragon's neck. Yay!

Stuff I ain't fixing:
- Diving gear and its related accessories are internally helmets. I do not stop helmets from rendering, even the odd-looking ones. Not fixing this. I'd have to manually hand-pick every helmet in the game and choose if I want to add it to a blacklist or not.
- Solar flare shield ain't my fault and it's not even that bad imo.
- Robes. Don't wear robes.
- The sniper rifle zoom thing actually does happen with beds, just not chests.
- I ain't fixing the portal gun. Mounts don't even let you pass through portals, at least the big dragon can in the right circumstances (or just crouching).
- Djinn's... I'm not going to try and fix. It makes the dragon look kinda funny tho
- The Royal Scepter is technically a 'balloon' which I allow the rendering of.
- Lilith's necklace and other transformations, to my knowledge, have no sane way to check if they are actually transformations or not. There's a good reason why I disabled mounted rendering by default, and why there's a warning on the config screen that turning the mounted invisibility option off tends to cause visual glitches.

Thank you again for all the reports, and I apologise that I'm basically dismissing over half of them 😅

Yea don't worry, I figured many of those anomalies would be impractical to fix, so might as well log as many as I can :P
I do have one actual suggestion: currently, B'ig dragons still show the dragon armors despite the models obvisouly not matching; with how you can use Gems of Shaping to transform back and forth, it would make sense for them to not render while big? No idea how it actually works in the code so no worries if it's impractical

Currently, the way armour works is that all items have a new 'fitsOnDragon' flag. It's true for dragon items, false for everything else, and controls if that item should render in the body/leggings slots of dragons or not.

I think I can make it so at least body armour and leggings won't ever render on other dragon types. I don't see any good case where you'd want body armour or leggings from one dragon on the other anyway, but helmets maybe, so I'll leave helmets to always render.

Dragon items will still render normally on non-dragon races though. I try to keep my code from touching the behaviour of non-dragon races as much as possible, so I won't be 'fixing' that for now.

...got an update out for that right now in v2.5.1 actually. It was shockingly simple to implement!

Oo nice; is it intended that you can use pedestals to set spawn anywhere (including outside valid housing) now?

Yep! I liked the idea of it, and realised it was something I could do after fixing some of the other jank with pedestals.

Neat, good to know!
I was trying out the other dependant races (Fishron and Dog) and well, both are capable of consuming the Breath Power Gems despite either not having a breath weapon (Dog) or having one that doesn't scale with it (Fishron) (Although, the Fishron bubble breath and twister might make sense to scale with that?)

Okay so this one I can't get to happen without the Directional Melee mod enabled, but it might just be coincidental so i'm reporting it anyways; while swinging things like tools at a steep downward angle, there seems to be a single frame where the B'ig dragon's legs are one pixel higher than normal? I don't really know what to make of it

Oop, I should probably just block the other races from using the breath power gems, considering they already can't use the other breath gems.
Fishron race breath currently scales with max health. I just haven't documented that because its future is still uncertain.

B'ig Dragon leg rendering is a bit janky under the hood, so I wouldn't be surprised if there are little hiccups like that with other mods. I haven't used Directional Melee myself though.

I know messing with projectiles is... dubious at best, but I do notice that the projectile origin (or well, at least the flail chain origin) on b'ig dragons is off-center (to the right), is that like set in stone?

Yep. All projectiles in the game spawn at your character's 'origin point' or a hard-coded position relative to that. This usually ends up being the dead center of your screen.
edit: I say 'all projectiles', but I really mean 'most'. I'm aware there are some odd exceptions, like Starfury. The point is: projectiles spawn at hard-coded locations.

I tried playing around with it a while ago, but it had disastrous consequences. I was able to offset the position of projectiles, but then they were aiming NOT at your cursor because the logic for their velocity+direction has already run prior.
At that point, the parameters used for aiming the projectile are not available any more, so it's not possible to 're-align' the projectile's aiming direction in any sensible way.

...I should add, this affects some odd things you might think are 'swung', like shortswords and spears. These are actually implemented as projectiles, so they suffer the same problem of spawning at your origin point and not the same place that swung items like pickaxes position themselves at.

Yea that tracks, it was worth a shot I suppose; I'm somewhat surprised it seems anchored to the right of the widened hitbox instead of the left (or even center) ¯\_(ツ)_/¯