Classic fights revisit edition 2: Canelo Alvarez vs GGG 2

Officials are being discouraged - by the commisions - from scoring even rounds for quite some time now, which is why We rarely see them.
It might not be officially prohibited, but I think sticking to guidelines that officials are subjected to makes sense if We want to "judge the judges". Otherwise it becomes sort of a fantasy, like making up our own criteria when the judges work within different system.

The same with making clear rounds 10:8 and close rounds 10:9 like @ETM suggested. There were other scoring system that gave judges more space here, like the one used in Argentina until not long ago(Maybe it still is, not sure). Under that system, clear rounds were scored 10:9, while close rounds were scored 10:9,5.
With the regular 10 point system We see used in most of the world and in all major title fights, 10:8 rounds without knock-downs are - in practice - reserved only to those 3 minute periods where one fighters takes a bad beating or is seriously hurt.

 

I agree, if a round is so close you cant decide who won it, make it even. You don't want to decide a extremely important fight on a coin toss. For that matter ang fight, to the boxer themselves, any fight is extremely important.