Personally, I only have an issue with how you can stuff a vest, regardless of its design and number of pouches, but I've made a separate ticket about it:
Since then, I've made the following observations regarding weight system:
With underwear only, it took 31 seconds to cover the distance (average speed 23km/h).
With 30% load (standard BLUFOR rifleman loadout), it took 42 seconds (17km/h).
With 70% load (rifleman + full carryall backpack + full inventory + NLAW + MX GL with suppressor), it took 44 seconds (16km/h).
The only differences were, how soon I wasn't able to sprint anymore, hence differences in times, and how soon heavy breathing sound effects appeared.
In another experiment, 70% loaded AI was happily jogging at the same speed, as my lightly loaded rifleman, while for real his speed should be limited, with the possibility to limit it even more, if jogging for an extreme distance. Not even jogging the entire Stratis airbase runway up and down (2km) would tire the encumbered soldier (9 minutes, 13.3km/h, no sprint was used).
It looks like increase in load doesn't influence soldiers' speed, nor ability to jog. Only sprint is affected. A guy in underwear has the same jogging capability, as a heavily loaded man. Straight and level runway is easy, but it's the same for walking around hills.
Jogging uphill over 30-40 degrees inclined terrain, with 70% load, is perfectly fine. Breathing sounds and blur are there, but they don't have any tactical impact. You can storm a hill all day long if you like, which is wrong and lessens the strategic importance of holding high terrain. Also currently it makes little to no sense to drop backpacks and not needed launchers, when storming enemy's positions, as you do for real.
Personally I have completed all-night-long marches (with running and jogging stages within them) with weapon, gear and full backpack and inevitably our pace was slowing down to a walk, while at that time I could have run 8km under 40 minutes, without all the gear (average speed at least 12km/h). This is (or used to be) US Rangers standard run, yet in Arma 3 fully loaded soldiers, with bulky NLAW, backpack and all the stuff can run even faster and without further tiring.
I understand certain gameplay-wise limits and design decisions, but currently the weight system doesn't do anything significant to soldiers' movement abilities (you can sprint for so short distance, that you can entirely forget about it) and doesn't force players and mission designers to take soldiers' load into consideration. For example, vehicles would be very useful for hauling the gear around, even the ATVs, but now they are used only as quick means of transport and additional firepower.
Gear means (kg):
A comparison of certain Arma 3 items with their real counterparts:
M320 rifle weighs 9.7% or 11.4kg, which is less than Cheytac M200 14kg (both empty and without scope).
The ghillie suit weighs 6.3% or 7.4kg. Real ghillie jacket with standard pants and shoes, like used ingame, weighs about 5.1kg total.
Standard rifleman uniform weighs 5.7% or 6.7kg. By my estimates, two piece uniform + shoes should weigh about 3.5kg.
Loaded NLAW weighs 9.7%, which would give 11.4kg versus real NLAW 19kg (launcher 12.5 + missile 6.5).
Loaded MX without attachments weighs 3.4%, which gives 4kg. Close to SCAR-L 4kg and M4 3kg (both loaded with 30-rounds mag).
ECH helmet weighs 6.3% or 7.4kg! Compare that to PASGT helmet 1.4 - 1.9kg or MICH helmet 1.3 - 1.6kg. No radio gear would be that heavy, not even with NVG fitted.
Carrier Lite weighs 3.4% or 4kg. This indicates, that it isn't fitted with any additional ballistic plates, which alone add about 7 kg.
Katiba weighs 2.3% or 2.7kg. Real Khaybar weighs 3.7kg (both with empty mag).
OPFOR helmet weighs 8.6% or 10kg. Supposedly it contains some crazy electronic package, but that's a serious overkill, with regards to human comfort and ergonomics. Maybe it's Russian computer there? ;) One Russian aviator told me, why Su-27 is so much bigger, than MiG-29 - they had to install fly-by-wire computers in there... :D
EBR weighs 4% or 4.7kg, while the real thing weighs 5.1kg - this is close enough.
Lynx GM6 weighs 13.7% or 16kg. Real one weighs 11.5kg (both with scope and with empty mag).
Just out of curiosity, community addon Colt M4. 2.8% or 3.4kg loaded, real is 3kg loaded. Close.
% were measured from screenshots, real weight in kg was researched. Certain items in Arma 3 are close to their real counterparts, which indicates, that my estimation of 100% load as 118kg could be more or less correct. Caseless ammunition is lighter, than standard brass-enveloped cartridges, available sources for smaller callibre caseless ammunition claim about 50% reduction in weight, as compared to 5.56mm NATO rounds. I think that 6.5mm caseless *could* be calculated as 55-60% weight of 5.56mm NATO (=0.3kg per one 30-rounds mag).