Incidentally, IIRC to the statement that started this discussion, there is no functional difference between a 19 con dwarf and a 18 con anyone else Fighter. They both get +4 hp per die.
You remember wrongly. No idea about tabletop 1st edition rules, but both in 2nd Ed, and in the Krynn trilogy, 19 Con gets you +5 hp. I just rolled up a new character in DQK to check - a level 12 dwarf fighter with 19 Con starts with up to 144 hp. 18 Con gets you 135. What makes the dwarf worthwhile as a dragon lance wielder is that single class fighters will outpace all other characters for total hit points. At the end of DQK, my dwarf had about 30 hp more than my knight.
It's been years since I last played the trilogy, so my own memory may also be a bit spotty, but I'm fairly certain that on the highest difficulty (+50% enemy hp), it usually takes more than a single DBF to take out a dragon; but a hasted fighter can take out up to 4 each turn. And at least in DQK, the major dragon encounters tend to be scattered enough that you can't cover them all under one DBF.
Your experience might have been different, but that's how I played with three mages and two lancers - stack DBFs on clusters of enemies, take out the stragglers with dragon lances. And it worked very well. You may say that a dwarf with 150-200 hp is overkill, but having warriors that can soak a breath attack (save for half damage), and still one-shot dragons afterwards gives you a certain peace of mind.