I submit to your lack of authority!
Finalish thoughts on Dagath:
[debating on whether or not it's worth an aura forma to get off of Brief Respite; I'm running lowish on them after having put them on every prime frame and it's been ages since I've run arbitration. Yes, Archon Flow over Flow Prime is a mistake there, but I'm not going to get Primed Surefooted onto this anyway, no explosions for Dagath!]
Power Strength breakdowns:
258 for 90% slow / 90% damage redirection / 90% defense reduction
288 for 95% / 100% / 100%
There's no point going higher than 288 (slow is locked at 95%) other than damage buffs increasing
This build required one red Archon shard to get past the 258 breakpoint but being 88% slow really isn't a big deal.
In fact, I haven't decided between Blind Rage and Transient Fortitude yet: on the one hand, the additional crit damage via #3 doesn't take any energy per second, it's passive, so Blind Rage takes advantage of that fact. (It does push the horses to just shy of 80K damage which can be many times higher in the real world; or much, much lower, depending.) On the other, anything you Doom gets dead instantly, anyway, so having as many casts available to you as possible pushes me toward Transient Fortitude.
The passive where you can occasionally get 300% from Orbs, when combined with Arcane Energize and maybe a yellow Archon Shard makes me believe that hoarding energy with Flow is probably better than Efficiency mods. (And if you want multiple pets from the Bond mod for using 100+ energy spells, this might be the frame to do it!)
I put four Archon Shards into Dagath because she suits my proclivities: I'm one of those people who tries to make natural 200% crit weapons with perfect rivens + arcanes and stacks Vigilante mods to give them Red-Red crits. I have a mirage with 5 Red Tau Shards set to + secondary crit %. It's something I like to do since I'm into numbers.
OTOH, anything even in advanced normal play is instagibbed WELL SHORT of that, especially when I'm with Ars clan, and Dagath is a very glassy glass cannon. That one enemy standing behind you that your scythe didn't hit WILL mess you up, often lethally. And suddenly you're still alive but playing Warframe with green Vaseline smeared all over your monitor.
In that regard, Dagath is a frame designed for situations that don't really occur in Warframe: it lets you deal more targeted damage than is ever strictly necessary while being too squishy given that enemies spawn in from all directions when you're by yourself. All of her abilities are too limited in their vertical dimension to properly work in Warframe level design. If I weren't obsessed with numbers, I don't think I'd have invested this much in her and I'd only recommend her to other people with a similar obsession.
The one change I'd ask them to make is to make the cooldown for Grave Spirt to start immediately after you die: then, with 250% duration (Narrow Minded plus Primed Continuity), you could be invulnerable for the full 25 seconds of the cooldown and then have a brief time to cast Grave Spirit again. That's nothing that Revenant can't do now, costing less energy, and with fewer mods (and mods that don't upend the frame's actual goals like Narrow Minded would to Dagath). If people are allowed to play Warframe terribly with Revenant, they should be able to play Warframe terribly with Dagath...