Would the movie had been better if Joey and Terri been lovers ?

It would've added some more depth to the film but back in 1992 a lesbian subplot wasn't that common like it is now!

My mind drifted that way.

The original script was more suggestive with its lesbian subtext. Too bad that there wasn't a draft with more overt instances of lesbianism.

You can read the original subtext here: https://popcultmaster.com/2018/10/02/siamese-sequel/

As for the script in general: https://imsdb.com/scripts/Hellraiser-3-Hell-on-Earth.html

Of course the movie would have been better with some girl on girl action.