Well, @
spinozajack, that only works if the party can take unlimited short rests (at 1 hour apiece), so, forcing the all fighter party to expend resources isn't that hard. Plus, as the second wind doesn't really scale by level, that d10 healing gets left behind fairly easily.
Yeah, I can't help noticing that @
spinozajack 's argument depends, pretty centrally, on being at-or-near 1st level. Second Wind is AMAZING there, because you can restore your entire HP pool in one roll (if you're lucky). Or you can restore 2 HP (roll a 1, +1 for being a 1st level Fighter). Get up to 3rd level--the point at which the game really "begins" because the training wheels have (more or less) come off--and it's not nearly so insane. Not only do Clerics get their 2nd level spells (and have twice as many 1st level spells), they've also--from 2nd level--picked up their CD power and Domain feature. Strangely, Life Clerics actually get the Domain Feature a level earlier (despite the table saying it happens at level 2 for all types).
Regardless. A 3rd level Fighter with, let's say 14 Con, has (10+2) = 12 HP from first level, plus (5.5+2)*2 = 15 HP on average from levels 2 and 3 combined (or 16, if you use fixed values), for a total of 27-28 HP. Said Fighter can restore up to 13 HP on a lucky roll of Second Wind, and a minimum of 4, average (3+5.5) = 8.5 HP per short rest. (8.5/27)*100 = 31.48%, or on a lucky roll (13/27)*100 = 48.15%. So the Fighter can regain roughly a third of maximum HP, assuming neither high nor low Con investment. With "pseudo-dumped" Con (10), the HP value decreases by 6, to 21, meaning the percentages change to 40.48% and 61.90% for average and max, respectively. Is it good? Sure, it's supposed to be, it's a Fighter feature. Is it enough to make the Fighter overpowered? I would hesitate to say that. Even with a short rest after every combat, regaining a third of your health is big, but not insane; going with the expected 2-3 per day means getting back ROUGHLY your total HP over the whole day.
That is: at level 11, the Con 14 Fighter has (10+2)+(5.5+2)*10 = 12+75 = 87 HP (92 if using static values). Using Second Wind regenerates 1d10+11 HP, or 5.5+11 = 16.5 HP on average, or 21 for a lucky roll. That's (16.5/87)*100 = 18.97% on average, (21/87)*100 = 24.14% if lucky.
I've done an analysis (elsewhere) of the amount of healing a Cleric can contribute even without the Life domain. It's...substantially more than that value, even if the non-Life Cleric contributes only ~half its available slots as healing spells. With the Life domain, all bets are off; Preserve Life alone becomes a dominant part of party healing experienced. By level 11, it restores 55 HP--the equivalent of more than 3 Second Winds at that level--twice per short rest, for a total of 110 HP restored per rest without expending a single spell. And the points can be divided smoothly and evenly between party members, ensuring that there are no losses to over-healing. Even at level 3, it's restoring 15 HP a pop, which is straight-up better than Second Wind even if the Fighter consistently rolled 10s (10+level < level*5 is equivalent to level*4 > 10, which means level > 2.5). So Preserve Life becomes *strictly* better by level 3, and *worlds* better by level 6 when the Life Cleric can use it twice per rest.
Second Wind, like a number of other things, looks incredible at low levels because...well, low levels are low. Sequences always behave funny and have high divergence from the expected value when you look at their earliest members (consider that the first three ratios of consecutive Fibonacci numbers are 1, 2, 1.5--both of the first two values are pretty far off from the expected value, the golden ratio, but the sequence settles down quite nicely once you move away from its beginnings). For Second Wind, the healing as a percentage of health on average(/max), for a Con 14 Fighter, goes:
6.5/12*100 = 54.17% (11/12*100 = 91.67%)
7.5/19.5*100 = 31.48% (12/19.5*100 = 61.54%)
8.5/27*100 = 22.97% (13/27*100 = 48.15%)
9.5/34.5*100 = 27.54% (14/34.5*100 = 40.58%)
10.5/42*100 = 25.00% (15/42*100 = 35.71%)
So by 5th level, what once would on average give you over half your health (and could bring you to full) now gives on average a quarter of your health and can't ever give more than about a third. While a Life Cleric, just one level later, can restore 30 HP twice per rest, literally doubling the BEST possible result for a 5th-level Fighter.
It's a nice thing. But it's definitely not broken, and it is DEFINITELY not true that the party categorically loses by replacing a Fighter with a Cleric--at least if it's a Cleric of Life. And that's assuming said Cleric of Life NEVER spends any slots on healing.
Edit: If any Cleric--Life or not--spends just one slot per level known on healing, things can get pretty crazy. Especially if they focus on maxing their casting modifier. Assuming, for instance, an 8th level Cleric with 18 Wis, that's 10*(4.5+4) = 85 HP. (I'm ignoring over-healing losses because those can apply to the Fighters just as easily as the Cleric spells.) Now, compare that to assuming 3 uses of Second Wind per day at 13.5 average HP per use. A party of four Fighters gains 12*13.5 = 162 HP in total, but only 40.5 from any one Fighter's contributions; even if we up it to four uses, it's still only 54 HP per Fighter. Thus, the
generic Cleric (heh, rhyme) brings between 1.5 and 2 times as much healing mojo, with only 1 Cure spell of each spell level known, and can bring in other helpful spells to boot (and those precious high-level spells could be saved by swapping in an equivalent number of levels of lower spells, e.g. a 4th level slot can be adequately replaced by two 1st and one 2nd). If the Cleric had instead gone for 20 Wis at this point, it would actually be
better to cast low-level healing spells, because then the casting mod (5) would exceed the average die value (4.5) and thus result in overall more healing per spell level spent.
Edit II: Okay so I forgot that Preserve Life is limited to damage below half of max health. That's a valid criticism that weakens it noticeably. However, it's still highly useful; ironically, this means that it's actually best to blow Preserve Life during or immediately after combat, and save Second Wind (which CAN take you over half) for right before you take a short rest!
