I just sold a small 7.5 ft wide trailer (24 ft) that had a shallow slide (18"), and am getting a new 8 ft wide slightly longer (27 ft) that does not have a slide.
I like having a trailer that I know will not leak around the slide, and whose slide mechanism will not break. The new one feels more open than the old one, even though it has a dinette in addition to a sofa.
But our space needs are not great. I also know for some, the extra space provided by slides is nearly mandatory. But that's ok. It's why they still make both slide and non-slide models.
By the way, while I was in the process of selling mine trailer with the slide, it broke while running it out. That was a bummer.