Essentially what Zardoz said; You just need a healbot on your team, not a pet healer; He'll be able to heal you before the engagement, then heal others.
Besides, what's the problem with multiple loadouts? I have 3 AC loadouts.
I believe Health Amplifier allows for an interesting synergy where you need a healer before combat, but not in combat, as the healing wouldn't be efficient compared to when using the armour amp.
It is the equivalent to sacrificing half your health to take half damage, but also half healing, for 1 minute, and I find that infinitely more interesting than modules that just amp one stat. It also does all that without a two page description, thus being pretty much the epitome of complexity the devs have allowed into the game for now.
The key part of it is that it does not work in combat, you have to activate it beforehand.
I guess if it was to be less healer dependent, I could settle for it boosting selfrepair for 5 seconds so you'd be able to activate it on your own and get most of the bonus. I like to see it as the difference between "Resist" and "Nano-Mesh" overshields for Heavies in Planetside 2, or a channelled selfbuff over a reactive ability in some RPG, even though the mechanics are obviously different.
It should have a different application situation than armour amp, so bar any other considerations, I'm just against it being something that you just pop when you take damage just like armour amp.
Mind you, I could see an instant health boost module just fine with some penalty; I've long wanted an ability that somewhat prevents you from dying for a few seconds at a cost, and just granting you instant health would do that just fine, but it'd obviously have to be taken away afterwards, potentially killing the ship. Far as I know, health amp doesn't do that, however, if you're at 10k of 120k, you'll be at 10k of 60k when it runs out.
Edit: Of note, despite the long posts, I care about it more from a design perspective than a players perspective. As a player, I'm all for marginalizing healers, and I rarely play DN; I just don't want to reduce diversity.