Saeviomagy
Adventurer
The problem is that attacking a PC with 4 or 5 monsters at a time will be fine most of the time, but every so often the planets will align, everyone will hit or crit, and the guy will die. I'm not sure what steps you can take to avoid that without breaking the rules or fudging dice?I imagine that will happen if you don't take steps to prevent it.
"X and Y flank you"I want it to reward players unevenly, so that's good. I'm not so sure that it will take a very, very long time to declare actions; it's possible, I guess, but I don't see it going back and forth that often.
Do you have an example of a situation that could turn out like that?
"I move out of the flank"
repeat.
I mean that's a trivial example, and you're more likely to have a string of more and more elaborate maneuvers to avoid the inevitable, but it's still going to end when the DM says "right, that's enough, you're flanked and there's nothing you can do about it" or everyone gets bored.
The problem is that anytime ANYONE moves, the fighter can say "Oh, but he was next to me! OA!". I was perhaps exaggerating with combat challenge, but it's still going to come up more often than when there's a board there to show you that you're out of range.You can't do what you can't do. If you're a Fighter it doesn't matter how you describe your action, if the hobgoblin fighting you doesn't move and doesn't hit someone else, you're not getting an OA or your Combat Challenge.
If that happens, the PCs will get dogpiled and killed, just like you said!
In the first example (rogue and fighter vs. hobgoblin), the rogue saying "I hit it with my dagger" would have missed, since that's an attack against AC instead of Ref, and he wouldn't have had the +2 for flanking. What's more, the rogue can't say, "I flank him and use Deft Strike" because "Deft Strike" doesn't mean anything. No one can respond to "Deft Strike" the way they can respond to "I stab him with my stiletto through a weak point in his armour".
Well, first off, people are unlikely to take deft strike, because deft strike is the power that allows movement with an attack. Once you've made positioning this vague, the value of a 2 square move becomes pretty tiny compared with the other at-will options.
And what stops the rogue saying "I flank him and stab him through a weak point in his armor" each round (apart from every monster on the board saying "I take an OA!")? It's the same problem, just with different words.
I'm not saying that your system is particularly bad for this, just that it's not actually solving it.