After watching TPM and AOTC and CLONE WARS, it appears as though non-energy based weapons were used quite a bit. The Gungans even had energy balls wrapped up in a non-energy packet which could first penetrate energy shields to then open up and deliver the pain. Jango used some kind of seeking torpedo which was not energy based. Clone Wars armaments include conventional armaments (and even a laser which arcs to its target).
So, why didn't the Empire use similar technology to:
- attack Hoth
- attack the Falcon after Hoth
Why didn't the Rebellion use similar technology to:
- attack the Death Stars