The original Kiyone was interested in Tenchi. Naoko Hasegawa invented her (and Achika) in her novels that branched out after episode 6 of the OAV. The Mihoshi Special took Kiyone from those novels and animated Kiyone for the first time (as did TMiL1 take Achika and animated her first time).

In one scene in the novel Manatsu No Eve, Mayuka is confirmed by Washu (and dna testing) to be the daughter of Tenchi; Aeka and Sasami and Kiyone blush thinking they could be the mother (and hence Tenchi's future wife). In the movie, they replace Kiyone blushing with Mihoshi, and they have Kiyone chide them saying they are all too young to be thinking of that. Notice that the dress and everything else was retained and is the same between those two versions (but distinctive at the same time compared to other Tenchiverses):





That TU ignored this aspect of Kiyone's character is par for the course, they took away Mihoshi's, Sasami's, and Washu's attraction to Tenchi as well to play up the "love triangle" aspect.

I always liked Evil Kiyone, but I couldn't ever get into normal Kiyone.