I'm not sure what to answer here.
I never liked Troi's character too much, and how Marina Sirtis played the role. The result reminds me of the archetypal psychic – exactly the one who wouldn't have any telepathic abilities. And I was never convinced that she was suitable for her job that much, it felt as if only her telepathic abilities made her a counsellor, she seemed to lack good scientific knowledge of the mind to work as that, she was mostly used as an additional sensor on the ship – “I sense this”, “I sense that”, “I don't sense anything...” She had a few very good episodes, and she got better later on, but to me it felt like attempts to fix a character that hadn't be thought well enough and using the character's unintended flaws to the show's advantage. Oh, and they gave her an uniform and changed her hair style, both of which were significant improvements.
And I was in love with K'Ehleyr the first time she appeared, I watched the episodes where she appeared more than a dozen times.
But I'm not sure that she'd make a good regular, in fact I'd say she'd be worse as a regular. I'd be happy if she got more episodes in a larger arc though. And she wouldn't fit in the place of Troi, not to mention that there were many episodes that would be significantly worse if Troi wasn't there. My memory is not too good, but I think I'd miss her in “First Contact” (the movie; although she wasn't the usual Troi there), in “Parallels”, in “Disaster”, in “Thine Own Self”, and now I think to watch “Face of the Enemy” again.
In short, I'd prefer K'Ehleyr over Troi any time, but I'd say removing Troi from the show would be a terrible idea, and bringing too much K'Ehleyr in the show might not work either. So no.