No, you don't need it -- but personally I wouldn't throw it out, either. If I was at the point of running a third dragon for the same group of players (whether different campaign or not), I might be looking for something else to base the breath weapon on (assuming all three had had damage-dealing breath weapons). But unless there were other considerations that made it not the best choice, I'd certainly use it the first time.
And since Dragons only get to breathe X number of times based on age, and since they don't have to wait 1d4 rounds or whatever between using their breath weapon, they are more likely to be spewing non-stop for the first few rounds, if targets are present. That'd wake players up. That'd be something they wouldn't expect. For those reasons alone, it'd be worth doing, I think.
Given how dragon breath weapons work (X uses, no wait period), I think there's something I might awkwardly refer to as 'realism' in the idea of the potency trailing off, round by round, as the beast gets weaker.
It's not the only mechanic I'd audition for the role, but the audition tape is very good.
The scenario you sketch out sounds very cool, but very AD&D -- these dragons work differently. If you'd rather they not work how they do, then yeah, BW=HP is not the way to go. But the drunk slug was Godzilla for weeks, months, or years -- until the party figured out what to do (probably losing many members and/or hirelings along the way). I guess I'm asking: does the method just not fit with your idea of "dragon-ness", Sky?
Gnome Boy (a.k.a. "Jon") • DCC play-tester @ DDC 35, Feb 2011. • Beta DL 2111, 7:00 AM PT, 8 June 11.
Playing RPGs since 1977 • Quasi-occasional member of the Legion of 8th-Level Fighters - Holds the power to play gnomes at will!
Here Be DCC Monsters...
General Yoros, Warrior, Str 13, Agl 8 (10), Stm 17, Per 13, Int 11, Lck 8; Law, HP 39, AC 17, R+2, F+4, W+2, band/shld, warhammer, longsword, longbow, pitchfork
Han Dee, (Weaver) Neutral Thief, Str 10, Agi 13, Stm 11, Per 11, Int 15, Lck 14, AC 13 (Leather), HP 25, Luck Die d6, Backstab 3, Sneak Silently 10, Hide In Shadows 9, Pick Pocket 10, Climb Sheer 10, Pick Lock 9, Find Trap 9, Disable Trap 9, Forge Doc 10, Disguise 3, Read Lang 5, Handle Poison 3, Cast Scroll d14+2, birth augur (Born under the loom) +1 to all skill checks (including thief skills), Banepicks (auto pick lock/disable trap, but lose 1d3 random ability loss, if a 3 then 1 pt is perm)