There’s a large number of heroes that can pull that off, Ariel is just another one. She gets used a fair bit, average with a dispel and a mana buff, but I think my rosters would miss Misandra quite a bit more. I’ve still got Khagan and Brynhild who can feed that buff, and 4 other healers who dispel. C. Rigard really knocked Ariel down a peg too.
Now if you throw Misandra with one of those mana speed buffers, or Alby… sometimes both, you get something pretty ridiculous.
Ariel can stack with Alby/Misandra.
Khagan and Brynhild can boost mana regen but only for 3 heroes. Brynhild is just 4* while Khagan is slow.
I also own Misandra.
There is a reason why when SG release raid data around a year ago, Ariel is ranked number 1 as most used hero on raid offense.
A year ago, before C. Rigard and all. There’s plenty of times when fully charged Misandra fires, charges Ariel and Isarnia fully, and then you save 1 turn and whatever blue tiles you’d have wasted topping those heroes off. Ariel might help win over the next few turns, she’s really good, Misandra can win the raid now.
The point is, Ariel is replaceable in every aspect, Misandra not so much.
I don’t think this is the right place to debate over Ariel vs Misandra.
In my experience Ariel is irreplaceable. Misandra is too much of a gamble.
It is up to you to define your own play style/preference. Just so you know that most of other players simply have different preference.
Athena
Alby
Hel
Some old hotm are still among the nastiest
Still no better defense debuffer than Athena
It’s not because a hero is bad in defense that it’s underwhelming…
Natalya sucks in defense but she’s great in offense.
Greg is a killer against titans and good in a green stack
Musashi’s special sucks in defense but when tile damage is high in offense he basically gets back to full health when you launch them tiles.
If you don’t have a hero and judge them only how they perform when you meet them in defense you judge them poorly
Worst dark : Thoth, everyone agrees he’s useless, damage is not so good,. Minion is tough but only self without fun side effect… Boss wolf sucks too
Worst holy: norns, seriously ! OK G. Owl is even worse, he’s been a tiny bit better in beta for a few days but they eventually decided that he had to remain the worse hero in game. But norns still sucks, at least her damage is good. Worst holy hotm would be Neith to me.
Worst blue : Perseus. Although I remember the time when Aegir was so bad it was actually better to have only 4 heroes in defense 
Worst green : g. Chameleon, same uselessness as Norns.
Worst red : tough choice… There is no terrible red (although there are very few very good red too). Was Kong but he’s good now. Maybe JF, i ascended him but never use him. But that’s probably because other heroes do his job better
Oh, no doubt. I think I’ve encountered Hel once or twice though, despite her special skill being pretty great for the first of the HotMs. Athena is an interesting foe to have, as is Alby, who annoys me when I see him in war teams during Field Aid.
Kestrel…
Honestly? Valid. His special skill is too much of a situational thing to be effective, like with Vodnik. You’d have to wait until the enemy is a turn away from doing their special next or at around 70% mana for his special skill to be worthwhile. Other than that, he’s very… lackluster.
Excluding Marie and Finley, Sargasso is pretty neat against heroes you don’t want regaining a lot HP and Lady Locke is actually… kinda nice imo. I like that her special skill makes me think of Gill-Ra except she serenades you to death.
Perseus is quite useless, hit like a 4*, nature def buff is totally useless, compare to magni he is just big ■■■■
oh yeah he blocks healing…but well for 1 hero its not really usefull, i de better have a chao mana cut, its more efficient
his best skill is his element link… 
I have only 1 blue 5* but still fed him away right after i got him few months ago, even thorne is more usefull than him
IMO he doesnt need a buff, he just need to be removed from this game, this guy is an error 404
On my roster I’d have to go with Hatter and Grimble. Hatter could be fun and interesting if he were fast but I just faced a 10x emblemed version of him and he was kind of sad. Grimble may be worth something some day if they keep adding minions but for now he’s on the bench. If I keep crapping out on 5* purples I may level him on straight rage and frustration though. lol
I doubt Inari is the weakest, but she’s both quite underpowered and extremely niche, making her very undesirable and not worth ascending. If you’re going to make such a niche hero, they need to have some power. Definitely needs a buff. #buffinari
LOL, whaaaatt?! You’d keep Misandra (one of the weakest of the S2 heroes) over Ariel (THE BEST HEAER IN THE GAME)?? Ariel has two of the best skills in the game on top of the excellent healing! Cleanse and mana speed buff! You just don’t get better than that unless they made MN average speed. Misandra is a weak sniper and her skill of the moderate mana generation is pretty meh in action. It doesn’t seem to generate much mana. I think you’re alone on that Misandra over Ariel island! LOL
I have them both. I don’t think Missy as much of the sniper but living mana bottle. When Ariel is “on” and you launch Misandra who makes a chain hit, rest of the team are ready to go of too. Swell.
Thoth and Grimble are weakest hotms atm. You never see Grimble anywhere, Thoth might be seen from time to time in wars etc.
Or, in my case, if he’s the first 5* you draw and you have few other purple options at the time. 
As someone who is still working with mostly 4*s and has a fully maxed Grimble as her best hero then he feels powerful even though I know from reading these forums that there are much better heroes out there.
Personally, I really enjoy taking him along to various matches and seeing him eat minions, boost mana and survive longer than any of my 4*s.
I don’t know what you mean by that and yet at the same time I feel like I agree with it.
Sorry…just ca’t believe what i’ve read. I’d give 10 x Misandra for a Ariel even though i already have 2 of her maxed.
Natalya’s mana reduction is indeed good, but the burn in 4 turn leaves time to the burnt hero to shoot. Could be more effective.
Gregorion is the less underwhelming to me, the crit buff is indeed good. Saying that a hero is good in a stack is relative… also Elkanen gets better in stack (especially if you pair him with Evelyn and attack the ones she previously hit) but that doesn’t make him a good hero.
I don’t judge solely on the defense performance, rather more on overall utility. E.G. Poseidon can be used for everything, Musashi is much more limited.
I use Greg, Margret (2nd highest tile damage green), Eve, Wilbur, Tarlak high tile damage great buff, that’s my choice for blue titans
I use Wilbur on all titans no matter color other than reflect red rare, his buff keeps everyone alive and debuff increases everyone’s damage on titan stacked with Eve, gfalcon, gjackel, gpatnther, Frida element defense debuff