I liked "The Gift" a bit more than you although I do feel it was a flawed episode.
Jeri Ryan's performance as the Borg is a bit too emotional for me and doesn't ring that true considering she spent most of her life as a Borg without experiencing emotions, however the dialogue between her and Janeway was very good I thought. Kes probably deserved a whole episode without a B-plot but at least it was a good send off and I enjoyed that she saved Seven's life at the beginning linking the two characters together, her emotional scenes with Janeway were fantastic but her scene with Neelix was a bit of a cop-out. I also felt it was a shame that she didn't get a scene with Tom before she left.
Overall, it was a good, if very bittersweet episode. I definitely feel like Kes had a lot of potential left in her, much more than Chakotay or Harry.
If I'd been in charge, I would have built an extended airponic/arboretum type set and have Kes moved there as well as being in sickbay. The place could act like a sanctuary and Kes could act as a somewhat unofficial counsellor/sounding board. And I think Kes/Seven interaction would have been very interesting to see - Seven could have learned a lot about femininity and getting in touch with her emotions from Kes.
What a waste!