What are your thoughts on Edison?

That depends I suppose.

If you want him for farming dailies and such then I suppose he'd do the job as well as any other, though I personally think you'd be better off with an AoE Berserker if you have one. Edison's base attack, even with maxed Fou, is way too low for being a 4*.

If you plan to use him in harder content like high-level events, challenge quests and the like, then I'd have to say that would be difficult. I haven't used him much asides from borrowing and testing a friend's Edison as support, but he's too gimmicky for my taste.

His NP makes him a decent staller (especially with the upgrade later this year that let's him lower the enemy's ATK), and his skills make him an okay crit support. His third skill can boost someone's overcharge by two levels (very useful on the right servant like Tamamo's full party NP gauge boost) but his second skill has a cripplingly high cooldown despite its usefulness.

TL;DR Yes/Maybe for farming. No/Very iffy for harder content.

That's my opinion anyway.

Caster isn't a really good class for AoE, but Edison can help with farming at the very least. Go ahead and use him if he's your best caster available, but try to roll for someone more useful later on.

If you are looking for an offensive aoe caster, I would rather roll for the upcoming Da Vinci or have a buster based charles babbage to pair with merlin. Edison can work, but i woul only use him with tamamo.

I would try for others. I guess you missed the Halloween rerun, liz caster can deal decent damage for a caster. I second the chance on da Vinci's banner, her np can do as much damage to all enemies as medea can on one and is easy to np spam with a 50% gain and 10% gain over 5 turns. With kaleidoscope and waver she can almost do 3 turn farming by herself.

No casterliz? Condolences.

Casgil is the best non-wellfare AOE 4* caster.

I would go Paracelsus, for arts support, or Babbage, for buster brave chain.

Instead of saving for Da Vinci I would recomend to save for Caster Nero, from Summer...

I think he indeed has his shinning advantage, particularly his unique 3rd skill.
But, if picking up a caster has good offensive power, because of low 0.9 modifier and poor skills + undistinguished star wight from other casters + poor star generation, most casters are normally not a answer to kill, instead, Berserker can do the job.
Edison also has such issue, and his supprtive skill isnt that good (long CD, good NP effect but low NP gain). If you want to have him work good, other caster support and 2030 are required.
A common team if with 4060 Waver and Tamamo. You can try to put Edison's 3rd skill to Tamamo and make NP chain.
Overall, using him as main AOE Caster is a luxury option. But when you have all your team in high level skills, he isnt that bad. Babbage and Hohenheim are also not that good.

Without any sort of damage skill, sadly, Edison is a poor main AoE caster. That's not to say he's useless however.

One of my favorite uses for him is to pair him with Jekyll/Hyde while putting devilish boudevista on Hyde as well. A great way to turn Hyde into absolute buster monster, and Edison is the only one who can do it.

He needs a buff.

Shapeshift is shapeshift. Just a mediocre skill that helps with staying.

Mass Production, in essence, is not a bad skill. The combination of innocent monster and np charge per turn. But its cooldown is way too long for what it is.

Concept improvement is supposed to be Edison's calling card and his niche. Except when he's introduced, DW haven't put too much thoughts into the actual utility behind Overcharging NP. And the fact that Demonic Bodhisattva became a thing wildly nullifies his niche. The bonus star generation is capped at 30% at Max level, and only one turn. It's just a cherry on top.

His cards/deck are okay. Nothing spectacular. 3 hits on Q and 5 hits on Ex can be somewhat enticing depending on the situation, but the fact that he only has only 7.9k ATK combined with caster class mod makes every master that runs him think twice on actually using his card.

The effects behind his NP is probably the only reason why people run him. A guaranteed AOE NP/Skill seal with ATK/Crit down can be powerful in specific nodes.

Edison can be really useful in his niche, but his niche isn't dealing damage.

I believe even Geronimo does more NP damage than Edison does, so for farming, you're probably better off with an AOE berserker or even neutral damage.

Use him to support OCs and debuff stuff...for example you can use him to make Nitocris instakill guaranteed for silver enemies.

He's garbage for damage though, NP1 Edison deals the same amount of damage as NP1 Shakespeare. So you can make yourself an idea.

Don't worry about Caster Liz, she sucks too. If anything, later on we will get Sieg from the Apocrypha event and he deals more damage than Caster Liz and can loop his NP just like Summer Mordred. Helena and Nitocris are extremely useful options too, since they are permanent you can bump into one of them later on.

For anything else, stick to your zerkers.