It's not you. They all do sound different.

The theatrical 5.1 ac3 is extremely detailed-especially in the dialogue and ADR. (perhaps too much.) The theatrical Dolby Stereo track (LD PCM) has great midrange and low end but lacks the clarity on the highs in the ac3.

The 5.1 remix on SE DVD/BD is somewhere between the two, but without the detail or range of either, as if it had been cleaned up and remixed to be more polite.

The Dolby Stereo tracks for Raiders and Temple on LD are knockouts. I don't see why the WS LD of Raiders should be remixed, all the effects sound the same as the 5.1, and the panning is wonderful. Additionally the PCM of Temple is so good I may prefer it to the 5.1. I can't remember if Temple and Crusade had their mixes taken from 70mm.

And as we know, the Raiders mix was "sweetened" i.e. remixed with new effects from the ground up by Ben Burtt for the BD release.