Reactive plates give you 15 more hp, 1% faster move speed, and 0.15 more repair at a cost of 17 more CPU and 21 more PG.

For reference the total PG of a MLT Gallente Frame is 25 PG; so, just the surplus PG needed to operate the plates is about the same as the entire PG allotment on a MLT suit.

Seems to be working as intended then, the MLT frame is not meant to be a powerhouse, it is meant to be food for the grinder.

Small Fitting Tip.

As a general rule of thumb when fitting a Drop Suit a module of the same level as the suit will allow you to place modules in each slot of the same level. This can at times not be entirely accurate when fitting Proto Suits as the CPU/PG are dependent on various other skills in the tree than just your DS skill level.

What this means.

For someone who has skilled there Dropsuit Upgrades, Electronics, and Engineering skills to LV5, their MLT Dropsuit would have more than the base PG/CPU and certainly have more room to fit the reactive plates.

If 1.8 is a big infantry update, perhaps it can be properly inserted there.

This is with new numbers and bonuses:

A)
2 x Complex Reactive
66 hp, 1% speed penalty, 2 hp/s repair @ 36 CPU 16 PG
=
132 hp, 2% speed penalty, 4 hp/s @ 72 CPU 32 PG

B)
1 Enhanced Plate
117 hp, 3% speed penalty @ 20 CPU 6 PG
&
1 Enhanced Armor repairer
3.45 hp/s @ 35 CPU 5 PG
=
117 hp, 3% speed penalty, 3.45 hp/s 55 CPU 11 PG

A.----vs.----B.
132 vs. 117 hp
2% vs. 3% speed penalty
4 vs. 3.45 hp/s repair
72 vs. 55 CPU
32 vs. 11 PG

Results?
Reactive plates give you 15 more hp, 1% faster move speed, and 0.15 more repair at a cost of 17 more CPU and 21 more PG.

For reference the total PG of a MLT Gallente Frame is 25 PG; so, just the surplus PG needed to operate the plates is about the same as the entire PG allotment on a MLT suit.

How popular would a low slot module that gives 15 hp, 0.15 repair, and subtracts 1% from move penalty be at 17 CPU 21 PG I wonder?

Sort of... it gets better:

SP cost:
A) requires Armor Plating 5
Total: 932,760 SP

B) requires Armor Plating 3 and Armor Repair Systems 3
cost 205,200 SP x 2
Total: 410,400 SP

You get:
15 more hp, 1% faster move speed, and 0.15 more repair at a cost of 17 more CPU and 21 more PG
AFTER you spend 522,360 MORE SP. You have to spend over twice as much SP for plates that are notably worse than these ADV modules.

Edit:

Here's some potential Reactive stats I was brainstorming with a few pages in. These would require both Armor Plate and Armor Repairer skills for each rank:

15/4 - 50hp, 2%, 1hp/s
30/10 - 70hp, 3%, 2hp/s
45/17 - 90hp, 4%, 3hp/s

Seem more useful?

They don't need more Hp they need the same PG/CPU than Normal Plates.