I am currently contemplating by what percentage I should inflate the health pools of Exalts - away from the standard seven - to make room for something like "being able to take a hit", "being able to use Resistance as a main-line defensive tree" and "not getting wrecked in one good hit".
Right now, I am looking at anything from tripling to quintupling health levels - so, roughly twenty to thirty five.
Does this make combat longer? Yes. Does this mean that both villains and heroes actually have a chance to escape when the fight goes bad, instead of getting splattered in one hit? Yes. Is it worth it? Maybe.
So, what'Dy ou suggest?
Bit late, but 20 to 35 HLs is over reacting. By a lot, considering best Ox Bodies give you is 20. That goes doubly if your using 2.5, where it is actually hard to one shot splatter a guy. You need in the neighborhood of 20 post soak dice to reliably do it, and assuming people are wearing any armor at all, that's nigh impossible to do. Well, excluding magic flurries, which are the single thing most likely to kill players by accident these days. But using Resistance/Stamina as a mainline defense is viable as is. Stamina is better, since it tends to give more keyword coverage. More health levels doesn't really solve the escape issue, Athletics solves that one (and for Solars at least, gets you an all important flurry breaker).
My advice, using what havocfett gave you, tailored to Exalted:
First: High Stamina gives a small amount of extra health levels. (A -0 at 3, a -1 at 5, a -2 at 7, etc.)
This works (and has been oft suggested), but be advised the -2 at Sta 7 causes some weird effects with Attribute Excellencies. Might be best to just drop it, as only Alchemicals will even be able to get Sta 7 (fuck Elders).
Second: One -0 Health Level for each dot of essence
Again, works fine, but be advised Alchies already get this (at the -2 level) on account of their machine natures. Alchies are going to find it very easy to have ALL THE HEALTH LEVELS, but that is somewhat fitting with the splat.
Third: Extra Health Levels are either a cheaper or b a lot more abundant. (The Extra Health Levels Augmentation. Which is 2*-0 HLs and 2*-2 HLs)
I don't know Abberant, but the main issue with Exalted is Ox Bodies are boring but helpful, to outright necessary, depending on your role in combat and build. So most people don't invest at all in them unless they need to. The main way I see this dealt with is by giving out freebies, usually in one of two forms:
Stat based: Pick a stat (Stamina, Resistance or Essence are popular) and hand out Ox Bodies equal to that. I don't really like this one, since I like the idea Exalted aren't that much more then mortals without investment, and sooner or later they max out. Which leads to the other...
Hardy keyword: This is Sunder the Gold's brainchild from the old White Wolf forums. Basically, it adds a keyword to select charms, and every time you buy a charm with that keyword, you get an Ox Body, up to the limit for that splat. Linked is the version I use for my campaign, which also includes suggestions for a minor uptick in power for DB and Sidereal Ox Bodies, which were a bit lacking.
Fourth: Very heavy armor gives you Ablative Health Levels. This can be Bypassed, but is pr. useful for most purposes.
For Exalted, I would recommend allowing artifact armor to subtract from Overwhelming values. Say, reduces the minimum damage value of oncoming attacks by (Rating-1), to a minimum of one die. Have it stack with the starmetal MM bonus.
There you go. Now don't be surprised if certain build become completely immortal on you (no, not only talking canon Lunars).