I guess it just depends on the instrument. I don't have any hard and fast preferences, unless they just slop over the line into some goofy "look what
I can do" kind of thing, that's not really playable without damaging it.
- Vine/Tree of Life; I've seen some of these on really old, fancy banjos and mandolins that were beautifully done, to the point that it's hard to imagine the instrument without it. Unfortunately, IMO far too many newer ones have sailed to "Goofy-looking Land". And the ones that haven't? Grand Ol' Opry stars can afford them; I can't..
- Special Shapes; much as I like them, the shark fin inlays on Ricks are really too big, and just a little out there. But, I'm not going to throw my 3 Ricks away because of that; they're how you know they're Ricks.... Blocks are OK, as long as they aren't obnoxiously large. And the abalone ones on My Carvin LB-20's ebony neck are. My Kramer Forum III has little MOP diamonds; which, considering what the bass looks like and when it was made, are a model of elegant restraint..

The "Vintage Thumbnail" markers on my Gretsch Broadkaster are an
excellent idea, IMO. Not too big; not too small; on the side of the fretboard where your hand never goes when you play; and always easy to see. I wish more instruments used them... As for other special shapes? Unless it's an Alembic, my attitude is usually "Meh"...
-Dots; They work; I'm used to them; most of my basses have them. Even my Gibson T-Bird has them. So does my Japanese Epiphone EA-260; but they're offset way to the "no hand" side of the neck - like the Gretsch, kinda...
-None; surprisingly, my Alembic Epic is the only bass I have with a bare fret board. Which would be fine if it was fretless; but, it's not. The naked ebony took some getting used to, and frankly, every time I play it, I feel kind of cheated. It's an
Alembic!! Where are
my ultra-hip, at-one-with-the universe inlays?!?!?
