I've searched the forums and don't see any suggestions like this, only requests for fixes or changes to cues or wave forms. I also see that the Beatgrid feature gets halfway to my request but not entirely, as my feature doesn't have to do with two tracks interacting:

FEATURE: The setting would enable a feature that has Serato automatically "drop the needle" or set the track start position to the very first detectable transient of the track.

Almost all (properly produced) music contains a silence buffer at the beginning and end of the track, to account for launch errors I'm assuming.
Now that Serato and other softwares are capable of launching samples of data reliably and accurately, this buffer shouldn't be necessary for the software (though it is still greatly welcomed in general).
With so much to think about when preparing a song (well, depending on what your style of DJing is), its easy to forget or not have time to spin the needle position to the transient--it's a such a minor non-obvious detail in the whole mix of things-- and when one is trying to drop a track on the fly, this can immediately throw their mix off.
According to Beatgrid's manual, that feature can sometimes erroneously set the downbeat on the first transient of the track, thus proving that the developers could make this happen on purpose if desired (without using Beatgrid of course).

If automatically setting the needle is an issue, at least add a setting that automatically sets a cue point at the transient.

I can say that I've heard a few DJs mumble about wishing this feature existed.
Hope it can be implemented,
Thanks.