I'm carrying on a firebug usefulness discussion from another thread, hence necroing this one. We started talking off-topic about whether the firebug was a good class or not, and I figured it'd make more sense to necro this thread and discuss it and let the other thread get back on topic.
I am a L6 firebug, and play them quite a bit on Normal/Hard when I go on to muck around. Very occassionally I'll use them on waves 1-3 on suicidal, normally to ensure that I'll survive until I can get the team sorted and swap to a proper perk. I don't use them on HoE.
I think they are excellent on Normal/Hard, and rank them as the best class to play with, period, on waves 1-4, and still very competitive until fleshpounds arrive.
I have almost no experience playing as a firebug on HoE, but had quite a bit of experience playing on suicidal when I first leveled to L6 a few months back.
The Damage Multiplier
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Grenades
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The OH SH*T Moment
Completely agree with this. This is the firebug's purpose, and he shouldn't be trying to solo kill mobs, except on lower levels.
The OH SH*T moment I agree with to an extent. Yes, it's handy to have a get-out-of-jail card, and in a pinch it is a very useful thing to be able to do. However, with the amount of flame ammo you have, it should REALLY be an utter last resort, which happens sometimes once per game.
However, two points: Firstly, DoT damage isn't steady. The first tick of damage will do considerably [less] than the final tick. A L6 firebug giving a zed a DoT from a flamethrower will deal 35-38 points of damage with the first tick from it, and 96-124 points with the final (actual figures). The DoT lasts for 10 seconds. Also note that a single puff of flame on (for example) a clot, will deal 28 points of damage, but the total damage including full DoT will be 668-812. The halfway point of the total damage comes approximately 7 seconds into a 10 second DoT.
If zeds don't receive the full 10 second DoT, it also means that they will not become crispened, which means the firebug's role as a damage multiplier will be greatly reduced.
As you already know, firebugs will be considerably less effective if their DoTs aren't able to take full effect.
Secondly, zeds move faster on higher difficulties. A clot on Normal will move at 105 units, but will move at 136.5 units on HoE. This is considerably faster, and will mean that zeds will get to you a lot quicker.
Put these two together, and you can see that on a lot of enclosed maps where zeds are first visible relatively close to the players, on higher difficulties, the DoT will not have enough time to finish it's entire duration before the zed gets into melee distance. Yes, on Mountain Pass in the right spot you'd have no trouble clipping a zed with a MAC10 from extreme distance and they'd have enough time to take the entire DoT before getting into combat, but Mountain Pass is the exception rather than the rule in terms of viewing distance.
Firing
The firebug has 3 distinct firing techniques.
The first is the most used technique; "The tap"
The second technique is the "Controlled burst."
The third technique if the "Hose Down."
Because of my above reasoning, I think that although 'the tap' is a viable strategy on lower levels, it won't deal nearly enough damage on higher modes before the zed reaches your lines. This means that the firebug will either only deal significantly less damage as on lower modes, or he is forced to only attack using the last two techniques. In which case, obviously, he will run out of fuel before the wave is over.
Note: All the figures I used are from Phada's weapons and specimen's guide.
No, I haven't played a bug on HoE, but I have played quite a bit as a bug on lower modes, and have played quite a bit on HoE, and can see the speed boost zeds have and do the maths.