I like both those suggestions about the mines. I play as an engineer and to be honest the punishing thing has really cut back on my mine laying. Nowadays I only place them in very visable areas or if I'm actually fighting a tank (runnig up behind and throwing a mine on the rear deck).
I would be preaching to the choir if I just went off about how awful the punish system is, and it is, but I really can't think of too many things that would work better. Since we need to work within the framework of the punish system my four main changes to it would be:
1. Default mode forgive. People saying that they were too busy to hit page up really isn't a great excuse. Maybe this would help avoid a few of those careless punishes.
2. Reduce the points lost. If you tk, even if the other person knows it was their fault and forgives you, you lose -2 automatically. I don't see why TKing should still take off points if the other guy doesn't mind. If you're forgiven you shouldn't lose any points or at most -1. Secondly the -4 for a punish is excessive, especially seeing as how so many people mindlessly punish no matter what. -2 would be appropriate in my opinion.
3. Stats tracking of punishes. People might have some more hesitation with hitting page down if they know that people looking up their stats will see what little punish monkeys they are.
4. Not being able to punish until you're actually dead. People that punish while 'critically wounded' really bug me. If it doesn't count as a death yet, why should you be able to punish? This one is a biggy for me because several times I've accidently team killed a medic and then run up, switched kits, revived him, got stuck playing as a medic and then looked down and saw that he punished me right off the bat.
For the record I only punish when it is 100% obviously intentional. This DOES NOT include being a dumbass, if you run me over while I'm trying to fix your tank, no punish. If I'm in close combat with an enemy and you through a nade in the mix, no punish (actually thinking about this one, if theres no apology I might punish, but still probably not). Blowing me up along with an enemy vehicle, no punish. Even if it is completly you're fault I will almost never (95+%) punish, with or without apology. With an apology I won't, period.
Basically to get a punish out of me you need to pointblank shoot me for no reason or slap some c4 onto my tank. This is why punish monkeys really bug me, in BF2 I've only intentionally TK'd once which was when I saw a Spec Ops C4 a friendly attack chopper that had hovered to take a flag. Still I've had probably well over 50% of my TKs punished. I actually can't think of the last time I hit page down.
Sorry for the length of this post (punishers bug me a lot) I hope any ok points I made didn't get too lost in the text. I guess I'll re-post a less rambling version somewhere else later.
Final point! So much of this could be avoided if there was a much lower requirement for vote kicking someone. I've seen someone with a -400+ score survive over 20 kick votes. In fact I don't think he ever got voted off.