People don’t understand how speed works. The problem is the formula of the movement delay. You are able to move only if next_move < world.time where next_move = last_move + movement_delay, movement_delay is base movement delay plus all the modifiers. Sounds simple right? But here is the catch: world.time updates only every half a tick. While modifiers can be less than half a tick. This is why there is no visible difference between running medium and heavy armor. They both fall in the same threshold, in the same half a tick. To make a difference you need to get more modifiers, like weeds, bonebreaks, weild delay etc. M4 is a decent armor, for example, and I personally pick it every time because of armor slots for mags. But as soon as you get your leg fracced, you become a literal snail, because it brings you to the next half a tick so to speak. While in light armor you still keep decent speed in most circumstances. Nonetheless, heavy armor is actually a good pick. Just you will kinda have to get surgery as soon as you get a bonebreak or two, while with light armor you can still be effective with a few fracs.
I would even say a blasphemous thing, but I feel like chasing speed is a bit overrated aside from some situations and weapons. You do absolutely need speed with some cqc guns like m39 (but probably not that much for m37, as you don’t try to catch up with runners, you wait for them to get to you). But with m41a chasing is not that crucial, in most fights you only get like 1-2 extra tiles of movement from wearing a lighter armor. Off-screen damage is actually broken, so just keeping shooting after the enemy escaped your screen will net you almost the same result. Also most xenos are not that fast and you can keep with them even in heavy armor off-weeds. So it’s really about what playstyle you prefer, and what enemy you are put against.
Probably another thing to consider, is the more you are dying, the more pressure you put on medics. If medics get overwhelmed, the front is very likely to collapse. So investing in your survivability might be even more valuable. I’d like to see a round where everyone takes heavy armor and becoming free caps.