>>28130560IMO, the problem isn't the number of Fire Pokemon, they've always been low in number, but their accessibility in D/P.
Think of this relative to each generation. Not counting starters, Gen 1 had a smaller pool of Pokemon to pick from. Gen 2 had two pre-E4 Fire-type options in any game despite the introduction of Slugma/Houndour plus the asinine evo stone issue, true, but fast-forward to Gen 4 D/P and we're looking at even less choices than Gen 2. 1 option, to be exact, if you didn't want to pick a Fire starter.
The entire Magby line itself was post-E4; you couldn't even get it without dual-slot in the Battle Zone. A fair number of people had disagreed with the debut of Houndour and Slugma being post-E4; and then with Magmortar's introduction this happened in D/P again despite the much-increased pool of Fire Pokemon - and they didn't even give you the Eevee option until post-E4.
There are times where I have no Fire-type on the team at all, it doesn't matter much to me. But for people who like Fire types that were NOT the Rapidash or Infernape lineage, I can imagine that it's kind of a shitty choice list, considering that they were 4 generations in by that time. Those people would bitch if secondary options were Slugma/Numel, but at least it wouldn't exacerbate the terrible 'dex distribution of D/P Sinnohdex in general.