Mitigation & Healing. If you're not being healed then the situation being 1v2 doesn't really change anything but if you are then the " extra HP = extra damage reduction " balance is quickly annihilated. The fact that you are taking much bigger hits means that (1) the enemy team will focus you more because they like big numbers and (2) My heals on you are going to be 20% less effective than my heals on other people. I'd rather heal somebody in Recruit gear than somebody in Rakata gear because the guy in PVE gear will go down far quicker than I can heal - often even in only 1 on 1 situations. You buy 1 or 2 extra hits but pay the price of being impossible to keep up in the long term.
Now, if you are ranged DPS and can hide at the back and avoid getting focused then the situation isn't quite so bad. Similarly, if you are a tank then the larger HP will often be more useful than the increased mitigation as long as you don't mind effectively being ablative armor for a healer and dying regularly (CC and taunts are unaffected by gear.) For anyone who is going to actually be directly attacked, though, Recruit gear is better.
Hmm. Interesting. I'm still trying to wrap my head around this. I get two vastly different results depending on enemy dps vs friendly heals.
My current PvE gear gets me 20k hp and 4853 armor for a total of 31% damage reduction.
My Recruit gear gets me 13k hp and 4332 armor for 28% damage reduction + 15% pvp damage reduction
Let's say I'm being focused by 2 people, each doing 1000 dps and being healed by a third for 1000 hps.
2000 dps - 31% damage reduction = 1380 dps - 1000 hps = 380 dps
20,000k / 380dps = 52 seconds to die
2000 dps - 43% damage reduction = 1140 dps - 1100 hps (10% expertise healing boost) = 40 dps
13,000k / 40dps = 325 seconds to die
If we add a third 1000 dps focusing fire, it looks like this:
3000 dps - 31% = 2070 dps - 1000 hps = 1070 dps
20,000 / 1070 = 19 seconds to die
3000 dps - 43% damage reduction = 1710 dps - 1100 hps = 610 dps
13,000 / 610 = 21 seconds to die
Correct me if my math is off here, but it seems that the more dps I'm taking (compared to healing) the less effective my Recruit gear will be relative to my PvE gear.