But why bother comparing such numbers, when they will never present themselves in a gameplay situation other than the fixed one you artificially created? Surely using such results as an average still provides a poor result when trying to factor in every other variable the game presents when in a match, which is what we're trying to balance.
Of course this is getting off topic isn't it...
Well, the topic is "the changes in engineering gameplay due to the new patch". We're talking about the those changes right now and try to put them into some basis we can discuss on. But I'm also good with us agreeing to disagree.
To your answer: Of course you could use a formula that uses variables as placeholders for adjustable skill of players, timing of shots, ammo used etc. but that wouldn't lead to something you can actually compare in this situation.
What I tried to show with those numbers
(back to the original original topic): Your usual weapon damages your ship and thus forces your engineers to repair until one of them is able to use the second weapon again. The flamer however now requires both of your engineers to run around and keep the ship up (which isn't that difficult since the hotfix), but more importantly: It also keeps you from helping out if you're needed elsewhere (some loadouts require both guns to be shooting and the way over there [junker's sideguns] is just too long for a gunner to run until the hull armor is repaired).
Sure, the engineer sometimes has to take over the work of some other classes (mainly using a weapon), but the gunner also repairs his guns (which usually is the engineers field of work) and a good captain knows the problems of playing each class. So I don't think just because the engineer sometimes has to do other classes jobs it's a boring gameplay - it gets much more interesting because you're not stuck on mindlessly hammering/spraying all the things.