Yeah, currently WYSIWYG tools generate pretty terrible SVG. Sketch is especially awful, Adobe almost as bad, Inkscape the least but still somewhat bad. SVGO helps sometimes with this, but it also sometimes chews up your document and spits out an empty SVG.
To my eye Inkscape was the worst, while Illustrator and Sketch were both OK'ish. Inkscape can create pretty complex transformations on groups that are not necessary. It can also easily screw up integer coordinates and somehow add fractions to them. It's a real shame. On one occasion I rewrote an SVG file generated by Inkscape and made it literally 20 times smaller. Something like from 200k to 10k. Never used the poor thing again.
Discovering this has helped me a lot. SVGO is great, but sometimes it breaks my SVGs. Saving as Optimized SVG from Inkscape has never caused problems and the file sizes are very close.
