I think for me, it's just the realisation that I'm more comfortable playing a short scale, and don't have to compromise to play one.
I have a Mustang PJ, a SBMM Ray and now a Maruszczyk custom that are all 30" scale, are well made, and sound great. The biggest turning point for me was strings - I get mine through Newtone here in the UK, and they're custom made to my exact gauge, material, core and length specifications, for ~£30-35 a set.
Now I can play a shortie with phenomenal pickups, the sound I want, and have the string tension and clarity I want even when tuning down to C#. I used to think I had to put up with a 34" scale bass for that, but now I don't.