As excited as I am to get demo and firebug, I really have to be honest and say that this skill tree is very underwhelming. The firebug skill tree looks much more thought out in comparison to this one. There's not a single skill in any of these tiers that I'd be dying to get.
Tier 1 - Technique
Grenade Supplier: Team can receive an extra grenade from you once per wave
OR
On Contact: Your dynamite blows up on contact with a zed
I don't understand why anyone would pick grenade supplier. The support perk already gives ammo and a grenade, so this is just a straight downgrade. Maybe if it fully restored grenades, I'd consider it. But the more important issue is the supplier perk in general's functionality. Oftentimes people don't ever pick up ammo from me because there's no visual indicator, so it goes completely unused. We don't need an even weaker version of that. I'm really hoping I'm misunderstanding what this perk actually does.
On contact looks alright I guess. I'd just pick it because the alternative is so useless.
Tier 2 - Resistance
Resistance: Reduce damage taken from explosives (for you and your team if they are close enough)
OR
Sacrifice: When you die, you trigger an explosion, hopefully getting your revenge
This is another case of one perk being completely superior. Sacrifice just seems like a gimmick that will be fun for a match or two then never get used again. I'd never gamble on dying being a good strategy. I'd maybe use it if I had a chance to explode every time I was hit with a melee attack, not just up and dying. With the way it is, just give me the resistance.
Tier 3 - Advanced Techniques
Door Traps: Weld slower, but doors you weld will explode when broken
OR
Siren Resistance: Grenades have a chance of not being destroyed by Siren screams
Door traps seems alright. I doubt I'd ever use it unless the siren resistance percentage was low enough where it didn't make much of a difference. Speaking of which, would just making grenades always ignore sirens be overpowered or something? Because personally I find RNG distasteful.
Tier 4 - Weapon Techniques
Off Perk: Do extra damage with off perk weapons
OR
On Perk: Increase reaction, stumble and knock down power for demo weapons
Well, these are actually useful. Do you want to go pure demo, or have some flexibility to defend yourself when enemies close in? Seems like a reasonable trade-off.
Tier 5 - Advanced Explosives
Zed Time Nuke: Explosives dish out massive radiation damage in zed time, poisoning zeds
OR
Zed Time Concussive Force: Explosions have a massive knockdown force in zed time
Well...ZED time perks are ZED time perks. I don't particularly care about them no matter what they do.
On a side note, I think there should be a tier that lets you choose between explosion radius and direct-impact damage. Or skills that let you reload faster, get more maximum ammo, chance to ignite ZEDs, etc.