I wanted to offer a 'final report' on the new adjustments. I just started a new character a day or two ago on the Constant seed, focusing on the Pew-Matic and other weird ranged weapons (like Blowgun, Snowball Cannon, Fossil Knives, etc.).
Thoughts on The Constant seed:
Early game is incredibly rough, probably harder than FTW (although I've never played that seed). You starve to death after ten minutes and the only early food source is hitting trees. It's very dark at night, Charlie kills you in the dark, and torches and campfires keep going out from rain so the paths were often unlit. An aboveground spider cave made exploring one side of my world pretty dangerous.
I actually really liked it. Early exploration is one of my favorite phases of the game, so this made it feel extra challenging. In the long run, it felt like 'expert mode' for exploring instead of for bosses. The hunger mechanic actually makes the merchant, angler, and travelling merchant important (for getting a net, for getting better fishing and having excuses to fish, and for buying pho and pad thai, respectively). I think it actually made the long game easier, because I remembered to constantly feed myself, keeping the buffs running.
Random Enemy drops:
I didn't get the bat bat this time, but I got the tentacle spike. I used it instead of my Butcher's Blade because the butcher's blade was so slow. I know you were worried about tentacle spike overshadowing butcher's blade, and I did prefer tentacle spike, but I found them very close in power. Even on the Constant seed, I got many banners worth of crimson monsters before getting the spike.
The Ham Bat is the second thing I've done after making it to hardmode (the first was getting a spider staff). The Ham Bat is absolutely excellent. It made me feel safe in Hardmode. It's strong, but not too strong (I got wrecked by a hallowed mimic right after getting it). It was easy to farm in the Constant seed due to its 10% drop rate, but only after I had another hardmode weapon (the spider staff) and only because the hallow spawned right through my snow biome. In most worlds, I never see a Pigron. It seemed about as easy to farm as the Frostbrand.
Deerclops drops:
Lucy is much better now, and it's all because of the range. I used her as my main sword the rest of pre-hardmode, and she does a pretty good job of keeping away early hardmode mobs, although DPS isn't great at that point. The fiery greatsword or night's edge would be better, but Lucy felt strong enough. In Expert prehardmode, jumping at enemies, I'd usually get hit once or twice before they die to Lucy.
The longer duration on the Weather Pain is great, it helped in boss fights. It's strong but not too strong; its pierce cap means it can take a bone serpent down to a sliver of its health but not kill it. Switching can still be a 'pain' but that's the tradeoff I suppose. Good against hungries on WoF.
The Houndius shootius definitely doesn't replace the OOA minions. When I had a cluster of mobs the explosive trap was much better at getting them. Houndius shootius was good at things like bats and demons. I liked having an extra sentry during OOA, especially for Wyverns.
The Pew-matic is SO much better after the buff! I used it against Skeletron and Wall of Flesh. In both cases it did okay. With Skeletron I forgot I was wearing the angler's hat, so it was a bit harder. With the Wall of Flesh, I had the bone glove, bone helm, rage potion, and an unreal modifier, as well as using Weather pain, and killed it in about 1/5 -1/6 of a medium world's length. To me it seemed worse against WoF than Bee's Knees or Hellwing Bow but better than most other things. And it's been great for knockback in hardmode, and the occasional 'strong' projectile helps overcome enemy defense, making it better for early hardmode than bee's knees or hellwing. It takes some practice to aim right. Overall, I think it's perfectly balanced, right around Handgun and Bee's Knees.
Bone helm is still awesome. How much damage does it do? It'd be nice to add to the wiki.
Other random:
I got two of the paintings and one hairstyle from DST.
Abigail's Flower was nice, again, but I was spending a lot of time in the underground desert, so I switched to Flinx early on for knockback.