It annoys me (and presumably others as well ..see feedback on Benjij) greatly to play against people who seek a corner of the map and build up all the time avoiding any confrontation and only at the very end come out and quote "surprise" the remaining players.
It helps if a number of other players are fools, of course , to make this lowlife "tactic" a succes...but as you have guessed, there are a lot of fools at hand.
Now, the RISK/CONQUER game philosophy is to CONQUER , ATTACK, be AGRESSIVE .. otherwise they would have called it "BUNKER" iso "CONQUER".
So help us with simple software measures to discourage this a-social playstyle.
I have a suggestion:
1) Keep track of a players Armies on the map (A), number of lands (B) and number of attack dice throws (D). If after his turn D is far below a threshold which depends on (A-B) then he'll lose immediately a number of new armies his next turn (in real life similarity; for having to nourish too many armies at a too small area (too small crops..soldiers starve or get mad).
Example: round 8: you start with 14 lands and have in total 35 armies in the field. You get new armies 4 plus 3 for a bonuszone and place them in your bonuszone. You attack a small army of 1 in your outer perimiter to obtain cheaply a card. You throw 3 attack against 1 defense and win.
You started the turn with 14 lands, 42 armies and you end the turn with 15 lands, 42 armies.
The threshold is (e.g.) use of 30% of your active armies like this:
(A-B)x0,30 = 9 and you have used 3 attack dices once; 3 is less than 9 hence you'll loose (9-3)/9 of your renewal army in the following turn.
So instead of getting (the same) 7 new armies, you'll receive 1/3 *7 = 2 armies the next turn.
That'll teach them!
Of course the threshold needs to be tuned, but something like this is very easy to implement.
Or do you have better suggestions ? PLease add them here.