1.
Like tactical vest it comes in 2 variations: one with 15% resistance and +1 DT, one with unshackled resistance and no DT bonus. First variation just simply suck. You receive one less damage per hit if that damage is low enough to target DT instead of resistance. It can be helpful early game but as game progresses damage gets higher and higher and DT becomes less relevant in favor of DR.
15% of DR is crap, even if you add +50% vs melee it's still too low and easily topped by leather armors.
Tactical vests at least can make use of that +1 DT variation if you're maxing DT using ceramic plating.
That's why i'm going to ignore 15% DR/+1 DT variation of Riot Gear for the rest of this post.
2.
Riot Gear is in medium armor category because it's encumbrance is 20%. Tactical Vest, on the other hand, is in light category - it has only 10% encumbrance. But the DR/DT of Riot Gear is same as that of Tactical Vest. It feels wrong.
When comparing Riot Gear to various types of leather armors it is just worse, in both DR and DT. If we add 50% vs melee things are getting better but still not good enough. Best Riot Gear i found (in store, i couldn't loot it anywhere) had 6 DT and about 30% DR. Multiply this by 1.5 vs melee and you get 45%/9. Best leather armors i found had 10 DT and it wasn't a single instance.
They had more DT vs anything that Riot Gear vs melee. That's crazy 
. Their DR wasn't that high but let's just do a comparison of armors i found:
Best Riot Gear vs melee: 30%/6 * 1.5 = 45%/9
Best Leather Armor vs melee: 35%/10 * 1.25 = 44%/12.5 (1.25 because it is Padded)
That was Rathound Leather. Pig would get higher DR and its DT would still top Riot Gear.
Not sure how DT would be rounded, but it is not important.
3.
Heavy metal armors have several resistances in addition to mechanical. It makes sense because you practically can't dodge with them so you need to absorb damage somehow.
However, Riot Gear doesn't get any extra resistances over light armor despite being medium. Sure, they don't limit your dodging abilities as much as metal armors but they could still use some extra resistances.
4.
Riot Gear's unique feature are shields. Mounting a shield adds lots of encumbrance and weight, bringing that armor closer to heavy category than medium. Armor with shield has about 50% encumbrance - that's absolutely enough to make dodging anything serious totally impractical. You need to rely on DR/DT and metal armors are clearly better at this. The biggest offender seems to be no bonus vs ranged attacks from shield.
What can be done?
I already made a thread about
Detachable Riot Shield.
It would surely help, but it's just fixing a glitch rather than buffing.
So, what really can be done?
1.
Either remove 15% DR variation or make it have better DR and/or DT.
2.
Boost DR/DT at least to the level of leather armors. Take DR from Pig Leather and DT from Rathound, perhaps? Or maybe average. This way Riot Gear would be better than Padded Leather Armors vs melee.
3.
We are getting some lovely environmental hazards in next update. That's sweet. And it just happens Riot Gear could use resistances vs those hazards.
Every self respecting rioters use Molotov Cocktails. If you want to start a riots better bring some Molotovs or nobody will treat you seriously. This is why it makes sense to give anti-riot forces some fire protection. Bio protection could be explained by gas mask that's part of riot helmet, but that's hardly an unique feature in Underrail (:
4.
Give bonus vs ranged to riot shields. That's perfectly logical. You can keep that shield in front of you all the time since it's either fully transparent or has a transparent window to allow vision. Chance to block could even be higher than chance to block melee but maybe there are balance reasons against it.
Sorted by importance would be: 2, 4, 3, 1.
TLDR:
Raise DR/DT, add fire (and bio) DR/DT, make shields useful vs ranged, remove armors with 15% mechanical DR.