Is there so little screen space that messages have to fit into one line and the game flow needs to be interrupted with a "more" prompt?
I prefer it this way. If there's a lot happening at once (e.g. several monsters casting spells, attacking, etc), I think it's best if the game shows one thing at a time.
"Monster X casts a spell, you are confused -MORE-"
Alright, what's next?
"Monster Y throws a rock, you are hit! -MORE-"
and so on...
It's a good pace, and allows me to verify each event.
If I end my turn and get 6 messages (events) all at once (no -MORE- prompt) it's much more likely that I miss something. And besides, I think it happens too fast. When I'm in a critical situation I think it's much more suspenseful to just verify one message at a time, each one making you sweat more
And what happens if I'm in a room with 4 weak monsters throwing stones at me from the opposite side, and decide to walk over and melee them?
"Monster 1 throws a rock, but misses! -MORE-"
"Monster 2 throws a rock, you are hit! -MORE-"
"Monster 3 throws a rock, you are hit! -MORE-"
"Monster 4 throws a rock, but misses! -MORE-"
*moves one step towards monsters*
"Monster 1 throws a rock, you are hit! -MORE-"
"Monster 2 throws a rock, you are hit! -MORE-"
"Monster 3 throws a rock, but misses! -MORE-"
"Monster 4 throws a rock, you are hit! -MORE-"
A few turns, a dozen -MORE- prompts later:
*Kills monster 4*
"Monster 1 throws a rock, you are hit! -MORE-"
"Monster 2 throws a rock, but misses! -MORE-"
"Monster 3 throws a rock, but misses! -MORE-"
This is bad because I knew the risks of crossing the room to kill the weak stone-throwing monsters when I made the decision - I don't need to be reminded four times a turn (+ 6 while killing them) of what they're doing. If the game removes some of those prompts through some arbitrary decision about which ones are "important", then I get the even-worse situation where I don't know how many prompts I need to clear to get through to the next turn. Especially if a key assigned to an action can clear -MORE- prompts, this can cause more player error than it prevents.
I prefer Cataclysm's way of doing this - if an enemy is sighted, it prevents all time-consuming actions until you activate Danger Mode (or whatever it's called) which is taken to mean that you're aware there are things nearby trying to kill you, and that you're paying attention to the message log.