NO, DO NOT INCREASE ARMOR ON SEDNA.
Increasing the amount of armor she got per level (rather than just giving her +200 armor at the start) is barely significant. By level 10 she would only have +4% mitigation than she does now. That is not a large amount of damage.
If she had 20% mitigation before this change, and you had 250 Weapon Damage, each hit would drop her by 200 damage. With 24% mitigation it would be 190. Since you only attack once every 1.2 seconds or so, this comes out to roughly +8 hps BUT ONLY IN COMBAT. If you won by 400 hp in a /50 second/ CONSTANT engagement, well, now it would be tied. And that's assuming no one uses any skills since Armor doesn't effect how much damage you take from skills. That is not a terrifying buff.
By level 20, she would have a full +8% mitigation which puts her on the SAME LEVEL (except Rook, who has a massive health pool to balance and would still have more effective HP) as other melee demigods. Before then she would still be weaker then them. Just not as much as she is now.
I'm not trying to buff Sedna's early or mid game, even though it would see a hardly-noticeable buff. I'm trying to make her more useful in Level 13+ fights since currently she has the HP pool of a ranged character at level 13, which means that she will be targeted in a 3v3 dogpile. Sure, she has a heal button, but that only works once every 3 seconds. I'm okay with her having a low hp pool, but after level 15 or so she simply cannot fight another Demigod 1v1 assuming there are giants on the table (and no, that's not fighting in a creep wave. That's fighting on top of the hp flag with both creep waves equal and hitting eachother/the demigods). The only good demigods she can partner with well last game for 2v2's are Oak and UB. UB has a massvie HP pool and she can hide behind him and heal him like crazy. With Oak she can actually engage, take damage, heal once, heal twice, get shielded, heal a third time. As I just said, in 3v3 dogpiles, she will always be targeted (since she has the small hp pool and is more suscepitable to BURST damage, which increasing Armor doesn't affect) and wont' be able to get more than a few heals off.
Sedna's weakness is lack of effective AoE (which means she can't deal with creeps/minions as well as others), low damage output for a melee demigod (in exchange for high regen). She currently is the only melee demigod who is rather ineffective late game.
Oak has Shield,
Rook is admittiably weaker late game because he has less times to set up a tower farm and enemy creeps tear it up, but he still can defend a locked friendly or a locked enemy portal flag better than everyone else but I still want to improve Rook's late game as well sooooo,
Erebus has Mass Charm which stuns enemy creep waves for 9 seconds allowing his to royally screw stuff up (also Mist is scaling and currently Bites' armor debuff is scaling as well),
UB has Ooze which is a scaling defense and is also a DPS machine.
DA has Shadow-Swap (Level 15 range is absurd) and then most of his active skills do insane DPS. He still can't 1v1 anyone particularily well but that is nothing special
Currently the only decent ranged demigod late game is Torch, and that is because of his insane creep-control. Cold Aura slows enemy creeps, Fire Aura strengthens his own, and many of his attacks are AoE to begin with.
I'd like to fix that and I /really/ don't think anyone's weakness should be "sucks ass late game". It doesn't have to be "WTFPWNT AWESOME late game" like DA or UB (with Acclimation). That is how the Queen is, and how Reg is, and look how popular they are to play? Of course, Sedna isn't an epic-fail late game like Queen or Reg but she still isn't on par with other melee characters late game. Giving her a small + armor/level bonus does this.
Edit:
I've been mostly looking at Effective HP as the medium for balancig this, since it is the most convient for me to look at. Of course, Effective HP doesn't take into account burst damage, which means that real-HP is typically much closer to the amount of damage you take before you die than Effective HP. Since Sedna has such a small HP pool, while I was playing with increasing Armor, a more drastic increase was making a smaller change. Looking at the raw numbers other demigods have, however, would bring Sedna to have a bit high Armor, more than I anticipated.
What I would do is increase both Sedna's and Rook's armor values by 5 per level, rather than what I was saying, by 10. I still think that Sedna needs some help Level 15+ but it doesn't look like just increasing her armor to bring effective HP into line with the rest of them is the way to do it.
