Wait I thought mecha were robots that were piloted. If it is then would Daijinryu not count as a mecha?

It's not really that specific. Plus if we went with that criteria, Daimugen would also be included.

I thought this show had some great looking mech suits but their fights, especially coming right on the heels of Zyuranger, were pretty lackluster. Most of the mech fights in Dairanger amounted to a couple of punches and then the finisher.

FYI, all of the zords are sentient beings. Also, Daijinryu suppose to also have a humanoid robot mode like Ryuseioh according to an official art book.

Wait even the yellow. blue, and green zords are sentient?

Technically, the "mecha" of Zyuranger and Dairanger are alive. Kakuranger as well, but more in the capacity of the combinations than anything there. Bio Robo was one of the first that toyed with sentience on any level, but Zyuranger ran with the idea wholeheartedly. Succeeding Sentai would alternate between "mecha" as machines and "mecha" as an umbrella term for "Giant, armored components/creatures which unite".

Yes, but only Daimugen talks. We have to wait until Go-onger for talking zords again.

Speaking of sentience, aren't the cube animals, otomonins, the zyudenryus, and Gosei Knight considered sentient? origamis too to a certain extent.

You're forgetting Abaranger.