I've also done a solo Healer playthrough. Here's my impressions, smallified because it's a wall:
-Pre-Hardmode, the Poison Prickler nearly trivializes all bosses. I say "nearly" because in order to hit with it, you have to get very close and risk taking contact damage or getting hit with projectiles point-blank, but the damage is so incredible it almost doesn't matter. The Crimson Scythe trivializes the Brain--you can literally just stand there and hold Attack in the second phase and you'll slowly win--and I imagine the Dark Scythe does the same for the Eater, plus they still do great damage to bosses at close range. This kind of builds a playstyle I really enjoy for pre-Hardmode Paladin (that's what I call solo/aggro Healer) of getting in boss' faces and throwing down. The Omen then feels sort of pointless--as a mid-range weapon, the Poison Prickler is simply stronger, and to hit multiple targets the Scythes are better if you don't mind getting risky. I literally overlapped the Granite Energy Storm with a Blood Harvest when it had all its Energies around it and shredded them, it was sort of sweet.
-Another mention is the Life Quartz Claymore. For early bosses, it's sweet for sustain, and it does decent damage. Its range is way too short and its arc way too awkward to actually use it against the bosses themselves, though--only bother hitting the minions with it, like the Grand Thunder Bird's hatchlings. For range, you're stuck with Radiant Water (longer range, bad damage) or Pills (shorter range, better damage, lingers in place so great for charging attacks) but they'll do just fine this early. That is until you can get the Poison Prickler. All bets are off then.
-Pre- and during-Mechanical Bosses, Paladin is sort of a painful class to play. Your best armor is the Warlock armor (the other armors simply don't have high enough power to kill the bosses before the night ends, partly because of the weapons really) and it has a whopping 21 defense. That's lower than the strongest pre-Hardmode Healer armor. By a hair, but still. Dark Contagion is really helpful for taking on Skeletron Prime, but your best weapons are the scythes and the Iridescent Staff for him. They don't do much damage, and worse, the Staff requires you to keep an eye on your Mana.
-Once you get some Hallowed Metal, you can make the Hallowed Scythe and the Holy Blessing. The Hallowed Scythe is good for taking on the Destroyer (but it still takes some dang doin'), and the Holy Blessing is your best option for taking the Twins on... which is sort of sad, because it's not very good. I had to set up my arena with teleporters at either end to even take second form Spazmatism down and it was not very fun.
-After that, you can get Broken Hero Scythes from Mothron, and that's where the fun begins. The Terra Scythe is simply one of the strongest Healer weapons, and even if you can't manage two Scythes, the True Blood Harvest is still fantastic. Either of them is very helpful for taking on Plantera, if you're careful. The Holy Staff can be used to heal yourself, and it's the most effective source I've found so far. If you combine it with the Lost Cross you have a pretty good source of panic heals if you set it up beforehand.
-Once Plantera is down, you can go to the Dungeon and oh boy. Fallen Paladin armor is simply the best armor. Sky-high defenses, damage reduction, life regen, and the highest damage bonuses on Healer armor--so good. The set bonus, like almost every set bonus, is useless in single player, but all the extra stats it gives make up for that. You can also get the Holy Hammer, which is the other best weapon. The Friendly Fire Staff and Spirit Bender's Staff aren't too strong, with the main issue being that they take mana and the Fallen Paladin armor is not equipped for that.
-Things start to go downhill from here. The next Radiant weapon you find is the Pill Popper, which doesn't have higher damage than the Holy Hammer. In fact, it's about the same, and it doesn't have homing or range. The Christmas Cheer is a worse Terra Scythe--less projectiles means less damage, the higher base power does not make up for it. The Terrarium Holy Scythe, again, is not stronger than the Terra Scythe--which is a problem, because by now the Terra Scythe is starting to fall behind, and so is the Holy Hammer. The Celestial Burst Staff, in theory, has higher DPS than the Holy Hammer, but its projectile velocity is poor, it has no homing, it's piercing so most of the shots are wasted, and it costs way too much mana. And once you finally punch your way through the Moon Lord, the Life or Death has less DPS than the Celestial Burst Staff, which means it's getting compared to the Holy Hammer... and it has about the same DPS, with slower projectiles and *a mana cost*.
-I couldn't beat the Ragnarok with just the Terra Scythe and Holy Hammer. I just couldn't. So out of pure curiosity I spawned in the Reality Slasher and Lucidity to see how they worked and was pleased with how absurdly powerful they are (I trashed them after testing, in case you're wondering). And I got to wondering, why such a jump? The Burst Staff's damage isn't even in the ballpark one block over, and it--oh. Right. After a certain point, Radiant weapons just start being about hurting enemies and healing allies at the same time, so as a result their damage is cut short. But the Ragnarok Healer weapons are pure damage. I don't see why Healer weapons need to be about healing when they already have dozens of healing tools to heal with, but it does mean that I have to take on the Moon Lord and the Ragnarok with equipment three or four gear tiers old because they're still the best ones. Maaan...
I'd like to see some weapon updates. Maybe actually add some lootable Radiant weapons to bosses and enemies--all the Healer drops from enemies are healing tools, which is sort of disappointing because there is, I feel, a simply excessive amount. When the Sunray Staff got added, I got really excited 'cause that *sounds* like a weapon, like there's no way right? But no, it's the thirty-third healing tool. I don't feel like that many is necessary, personally, but that might be my bias speaking.
EDIT: Wow, I didn't know that that word would get censored. That looks sort of funny, aha.
ler nearly trivializes all bosses. I say "nearly" because in order to hit with it, you have to get very close and risk taking contact damage or getting hit with projectiles point-blank, but the damage is so incredible it almost doesn't matter. The Crimson Scythe trivializes the Brain--you can literally just stand there and hold Attack in the second phase and you'll slowly win--and I imagine the Dark Scythe does the same for the Eater, plus they still do great damage to bosses at close range. This kind of builds a playstyle I really enjoy for pre-Hardmode Paladin (that's what I call solo/aggro Healer) of getting in boss' faces and throwing down. The Omen then feels sort of pointless--as a mid-range weapon, the Poison
