I'm a very laid-back DM. As long as the players are not breaking the rules, I'll go with what they do.
That being said, for any offense, there is a good defense (and for any good defense there is a good offense). If a player is exploiting a particular rule to the point where adventures are being cakewalked, then I would respond with the appropriate challenges to humble them enough to get them to understand the unrealistic nature of excessive and unrealistic optimization.
To combat a battlerager, just send in the blasters and shooters...to combat an intimidating spammer, bring in guys with high will saves (or special defenses/resistances/immunities against this sort of attack). Lasting Frost + Wintertouched? Immunity/big resistance to cold. For anything they throw at you, there's always some fun way to even the table and make for a fun and challenging adventure.
When monsters seem too weak, terrain and environmental features can make a huge difference, too.
If a player will go out of their way to put the time and skill into a character that makes specific use/abuse of some game rules, then I consider it a challenge to fight fire with fire DM's generally win out in this sort of battle anyway.
If a player will go out of their way to put the time and skill into a character that makes specific use/abuse of some game rules, then I consider it a challenge to fight fire with fire DM's generally win out in this sort of battle anyway.
No matter how many people play global thermonuclear war, everybody loses. As a default state, I think it works best if players and DMs both go into the game trying to help each other and pointing out things that seem wrong.
So, if the DM really loves throwing needlefang drake swarms and mad wraiths at the party, the PCs should mention if it makes things less fun for them. Similarly, the DM should mention that <this combination of abilities> is throwing the game balance out of whack.
House Rules
Powers
Guileful Switch: takes a standard action instead of a minor action.
Rain of Blows: Make 2 attack rolls against the same target, use the higher one. Hit does 2[W] + Str damage, and you make a secondary attack against the same target or a different target that does 2[W] + Str damage.
Touch of the Unicorn: (Swordmage Utility 6) This power can only heal damage taken within the last 10 minutes.
Feats
Righteous Rage of Tempus: Minor action: If the next melee attack you make before the end of your next turn hits, it does +1[W] damage on that single attack.
Weapon Expertise, Implement Expertise, and Focused Expertise: All characters gain their choice of one of these feats as a bonus feat at 5 level. It may be retrained to a different version of the feat.
Skills
No changes at present.
Equipment
Off Hand property: only grants bonuses when making an off-hand attack (as specified in certain ranger and fighter powers). This means that Tempest fighters gets +1 damage with melee and close attacks made with the primary weapon, and +2 damage to melee and close attacks made as an off-hand attack.
Double weapons: have a primary end and a secondary end. The Primary end is the larger damage die (if they are different), the secondary end has the Off-Hand property. You can choose to attack with either end of the weapon, but the secondary end doesn’t gain any benefit from the off-hand property if it is not making an off-hand attack.
Double Axe: change damage to 1d10/1d8.
Double Flail: change damage to 1d10/1d8. You hit yourself with the secondary end every time you hit an enemy with the primary end. (Seriously, who thought this would be a good idea?)
Double Sword: change damage to 1d8/1d6. Primary end is Heavy Blade, Secondary end is Light Blade.
Urgosh: Primary end is Axe (1d12), Secondary end is Spear (1d8). Dwarven weapon training gives a damage bonus with the primary end; Eladrin Soldier training gives a damage bonus with the secondary end. Either feat will grant you proficiency with the Urgosh.
Double Shortblade (new weapon): 1d6/1d6, Weapon Group: light blade, Properties: offhand, defensive.
Magic Items
Bloodclaw weapon: the power can only be used on one attack (made with that weapon) on your turn per round.
Reparation Apparatus: Does not work on Living Constructs.
Power Jewel: Only one power jewel may be used between long rests by a single character.
Rod of Reaving: does not deal damage on curses that are spread by the Rod of Corruption or similar effects.
I believe Unicorn's Touch also got a post by someone official in reference to LFR games suggesting that it would get changed, but to just run with it for now.