If he didn't, he then had the die available during his turn, and then once he rolled his attack and saw his result... he could then decided to use it for Glancing Blow if the numbers worked out, or if it didn't, he powered it into Strike damage.
This is how I read it too... that you can choose Deadly Strike when you hit, and Glancing Blow when you miss, no need to "guess" and choose the effect before rolling the attack.
I can imagine some gamers would not like this, saying that DS and GB would require intention
before rolling the attack, but in another interpretation they could be both possible results of doing the same thing i.e. attacking in a certain way, and then if you hit the result it extra damage and if you miss the result is... actually the same extra damage!
Perhaps this is ok, that what you do each combat changes, but within a combat you pretty much do the same thing. I just fear that it's a little bland for the player.
I would say that this happens if
the player is bland. But unfortunately it happens to a lot of people, probably all of us have fallen into the trap of just doing the same thing over and over and then complaining that it's the game's fault...
My bet is that the Wizard, which is typically the character that does different things every round, does so mostly as a consequence of vancian magic, i.e. she
doesn't have the chance of casting the same "good one" spell every round because of the limits of prepared spell slots. I can say that I've definitely seen several 3ed Sorcerers (which have less limitation of this sort) going the route of "as many fireballs as I can", then switching to their best 2nd level spell a few round, then Magic Missile until the are also depleted.
And of course it's also bland DM's fault... if the monsters all fight for damage, damage all the time, the players are going to do the same.
Let's face it, the most commonly seen tactical variations in a fight are these:
- doing something else because it doesn't work (e.g. monster has resistance)
- doing something else because you're out of attempts (e.g. no more highest-level slots)
- retreating because you're all low on HP
I think the designers have a tough job against DM/players' blandness, because even if all CS/ED options were pretty balanced, there is still a good chance that each PC (and monster) will stick to their favourite one and combat become a game of attrition. IMHO it's more in the hands of the DM (primarily) and the players to make a fight more dynamic.