Battlecards? Ok, I am using what I think is a cool name for a straight forward game mechanic: using a deck of playing cards instead of d6 for certain processes within the games.
As I work on the new BROE I am parsing what should go into the standard and "advanced" LOS and eventually Planetstorm.
There are at least 3 game mechanics that I have identified which, IMO, work better by using cards rather than d6.
First is initiative where you have multiple units and players. Under the BROE it is simple: roll 1d6 and add leadership, break ties with an additional roll, higher roll has the option to go first or second. In Planetstorm we used cards: draw one card per unit, draw additional cards for a unit that spends leadership or command and retain the best card, use a pass-or-play sequence from highest to lowest to allow each unit/player the option to act, low man on the totem pole must act if no one else does. Obviously, the latter is an order of magnitude more complex than the former but that is to be expected if you want to keep the same theory as applied to two units as to 10 units.
I found that it always worked well. It slowed play a bit but gave it more flavour. I bought a 1/4 size deck of cards from a dollar store and they work quite well. You can drop the card in the middle of the unit or stick it in a door base to stand up.
For LOS (as distinct from Planetstorm) there are a number of other game mechanics that could be imported and used with cards like the decimation rules. The experience/hero/leadership/command rules for campaigns needs to be looked at since it does not seem to produce results typical of the armies involved, and maybe using cards rather than 1d6 or 2d6 could work better.
If we look at Planetstorm, the first thing that comes to my mind is the Killl-Pin-Wound draft rules (posted in the media section). One commenter described this as brilliant but unworkable because it slowed gameplay too much. Read the draft and comment because it is too complex to immediatly discuss here.
Next is the morale rules. Under the original Planetstorm rules morale checks were on a 3d6 bell curve. As we worked more with this it all seemed to be a waste of time because most units were so hard to break. So what I was thinking of was to keep the basic conception but make morale checks a card draw which transforms the curve from 3d6/3-18 bell curve to a straight 1-13 draw. That makes breaking and rallying at the margins more likely.
Having said that, I prefer cards to goofy dice like d12, d20 etc etc for a few reasons.
First is that you can pick up a deck of cards for one or two bucks, if you don't already have one.
Second is that you can let the result lay, whereas you can't do that with dice unless you have lots of them.
Third is that cards can generate many wonderful, random patterns since they are essentially a d4/d13/d52 system with cross-referenced results.
So the bottom line is that my view is that the standard system should incorporate cards and card draws.