Stella Deus, Growlanser Generations, Yggdra Union, and Suikoden Tactics all came out around the same time Disgaea did. Also, this was around the time Wild Arms added an SRPG-like quality to its battle system. Of course, all of N1's other releases La Pucelle, Phantom Brave, etc. As well as non-N1-developed, but N1-translated titles like Generation of Chaos, Spectral Souls, and Astonishia Story came out. Most of these titles did little to effect the SRPG genre as whole, or even sell well themselves. They most likely were not expected to be smash hits from what I can tell, but they seemed to be riding the Disgaea hype train at the time. Honestly, you can argue that each of these games may have come out without Disgaea and I really can't -prove- otherwise, but it certainly seemed like Disgaea was having an effect at the time. Newer handheld titles still feel like they are riding the Disgaea wave to me, but it could just as easily be the FFT wave, I suppose. *shrug* The thing is that I'm not an expert on the subject, but the other points raised in this topic seem to be just as much anecdotal evidence as this.
-Djinn