Which are your thoughts on gadgets in Firestorm? I play Solo pretty much exclusively, so my takes are built largely around that. (Early and midgame ranking/ Lategame ranking)
Armor plates - Mandatory. One per pickup, stacks to five. There is never a time when you shouldn't be carrying as many of these as possible. A++/ A++
AT mines - My pick for the least useful. They're extremely rare, you get just one per pickup (maybe you can carry up to two, I've never checked), and with the closing circle there's never any traditional point to them. I guess you could theoretically try to use them aggressively like in standard MP, but why bother with the surplus of other AT weapons? Never worth the backpack slot. D-/ F
AP mines - slightly more useful. Again, just one per pickup and very rare, but they can be handy early on to set a trap and give yourself an advantage in a scary early fight. As the game goes on, though, they're just too much hassle and the damage isn't terribly worth it. D+/ D-
Dynamite - Two per pickup and stacks to four. Good for destruction, like when you know someone is camping in a little shed or under a first floor window sill. But there are a ton of cons. The magnetic stickiness prevents you from accurate placement when you'd like to get one through a window or doorway, you have to get very close, and swapping back to your weapon in a hurry is lethally slow. C+/ C+
AT grenade pistol - Poor man's Panzerfaust or rifle grenades. Two per pickup and stacks to four. Mediocre at a variety of roles, but should be solid against tanks. C/ C-
Rifle frag grenades - The anti-infantry gadget of choice. Two per pickup and stacks to four. Not something you want to use as a primary, but very handy for flushing campers out of cover or concealment. B+/ B
Panzerfaust - Three per pickup and stacks to six. And they do elevated damage against tanks, while being able to one-shot copters. Holy smokes. This is a big part of why vehicles have zero impact in Solos meta (and from what I can tell, not much more in Squads). They're poor against infantry, but they're solid at destruction. And you can carry six of them in one backpack slot. Six. B/ B-
Supply drop flare - Just one per pickup and stack. Drops a supply canister with random goodies in it. Can call attention to you, so use with caution. A-/ D
Vehicle drop flare - Just one per pickup and stack. Drops a random vehicle. Can call attention to you and vehicles suck, so don't use it unless you need to ride to beat the closing circle. D/ F
Revive syringe - Squad mode only. Revives faster and more reliably, IIRC. I'm not too knowledgeable about this one, but reviving seems to be a huge pain in Squads, so this is definitely a solid thing to have, especially late in the game when you don't have the luxury of space and time to deal with the slow, broken standard revive. C+/ A
Fuel/ Heavy ammo/ Light ammo - Won't go into much detail on these vehicle tools, they do what they say on the tin and are good for prolonging the usefulness of your vehicles, but vehicles are still bad. For whatever reason, vehicles start with low fuel and ammo, so you should generally use these immediately rather than dragging them around. D/ F.
Spotting flare gun - Two per pickup, stacks to two. Spots enemies in a large radius for several seconds. Enemies can also see the spotting, which (I'm pretty sure) the flare user is immune to, so you can use it to goad enemies into fighting each other. In my opinion, it's the best endgame gadget in the game, because knowledge truly is power. Note that the flare gun does make noise and have a visible trail from your position if an enemy is looking in that direction, so there is a risk of giving yourself away. A-/ A+
Artillery flare gun - One per pickup and stack. Hits a sizable area with a lengthy artillery bombardment that usually demolishes anything destructible in the radius. Marks the bombardment radius on the map for everyone, even enemies. It's possible to get kills, but more commonly it's used to push enemies out of an area. So this is best used very late in the game in the ultimate or penultimate circles to improve your chances of getting an actual advantage from this. Again, be aware of the noise and projectile trail when you fire it. C/ A-
V1 flare gun - The big daddy. One per pickup and stack. Calls in a V1 flying bomb, which does massive damage and destruction. Does not mark a radius for you or the enemies on the minimap, but there is a visible red marker on the ground itself and you can hear and see its approach. Use with caution, as I've seen many players kill themselves accidentally with this. Can be handy again for pushing enemies very late in the match, because they often don't know where to run and get more distracted than with an arty barrage. Also knocks players down if they survive the hit, which renders them temporarily helpless and easy to kill with gunfire. Use it late, use it with caution. B+/ A
Briefly on grenades, which I'm ranking generally rather than early versus late. (Pickup/ Stack)
Smoke (3/6) - A
Impact (2/2) - A-
Frag (2/3) - B
Incendiary (2/2) - D+
AT (2/2) - D
Sticky (2/2) - D-
I almost never use smoke grenades because I love anti-infantry damage gear, but their massive utility potential and huge amount you can carry makes them very valuable for maneuvers and giving yourself a chance to survive an ambush.
Anyway, I think that's about everything as of the time of this writing. Overall, the amount of gadgets is fairly good, though they could definitely add existing things like the PIAT, rifle smoke grenades, throwing knives, and perhaps a "limited ammo" repair tool to make vehicles more viable. But I think most players want new primary weapons more than new gadgets, myself included.