I use libreoffice under opensuse tumblweed, so I always get the latest updates. When I first downloaded LO=LibreOffice 3 months ago, it was fine, now it just became UNBEARABLY slow. mostly IMPRESS and DRAW. I have used LO under many Linux distros, and I always encountered this problem. I see many people reporting SLOWness issues under various versions, but NO solutions, or completely ignored by the LO community. under Debian, it became extremely slow, again after few months. some forum solutions providers suspected the files themselves corrupted, but I opened them in ABIWORD, or Calligra, without problems. removing LO and re-installing does not solve the problem.
so, LO can get very slow eventually after a fresh install, regardless of the distro, or gnome/kde/lxde etc and the version. I went to tumbleweed so I can get ongoing updates, and always run the latest, which was fine for 3 months, and suddenly just went down hill very fast.
Does the nature of the document make any difference? Are you using lots of tables?
I use LibO latest (currently Version: 5.2.2.2 / Build ID: 1:5.2.2-0ubuntu1~xenial) under both Ubuntu 16.04LTS and Mint (on a very old Samsung netbook) and it runs just fine on both. FWIW. (Not much, I realize.)
no tables in document. I use the same troubled LO documents by moving them to a fresh distro, fresh LO install, NO PROBLEMS for about 2-3 months and then the SLOWNESS starts, and that’s on all modules (writer, calc, impress, draw) (I dont use dbase)
It ran fine on debian for 3 months. moved files to a computer running OpenSuse-tumbleweed, also ran fine for 3 months and now LO impress, draw are unusable, calc OK but takes a long time to save a file, and somehow write is OK.