My Mini Lite has a kitchen slide. No plumbing issues so far (1 yr). My Coleman Sequoia had a swing-level galley. Had it 20 yrs with no plumbing issues.
Based on my reading of this forum over the years, I'm more worried about the slide mechanisms than the plumbing.
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10