I think there are two issues with going taller - aesthetic and engineering. By going taller you do risk its looking "odd" - but one of the knocks on lifelines is that those that don't ruin the look of smaller boats do end up being "trip" lines more than lifelines (or as one friend used to call them "death lines")
The other issue is that as you go taller, you will put proportionately higher forces on the bases and mounts in the event they are ever really tested.
For the ultimate in safety (but not attractive on a smaller boat, and quite costly) would be solid SS rails all around.
We sailed a boat without lifelines for many years - the only time anyone fell off was during a wild broach - and I'm not sure lifelines would have prevented those MOB events in any event.