Two leaders can make a HUGE difference. But yeah, I have run into the same problem as you. My group are all borderline powergamers, half of which are former Ultimate Delve champions. They know how to bring the pain.
I had been upping the encounter level of all my encounters but it still wasn't really threatening them, so I found a really good article by ChattyDM about 4e's "super secret synergy bonus" and how to account for it. It was very eye opening for me.
Essentially, as players begin to master 4e's complexities they become more difficult to challenge. They use smart tactics, they focus fire, they optimize their characters, and the develop nice combo attacks with their fellow party members. As a result combats of the appropriate level just become easier for them.
Read the article here:
Keeping up with the PCs: Part 1, The Secret Synergy Bonus : Critical Hits
And part 2 here:
Keeping up with the PCs: Part 2, What Not to Do and Quick Fixes : Critical Hits
So I implemented his suggestions and it made a HUGE difference in my game. Bottom line, I increased the damage output of monster and NPC attacks by +5 per tier per attack. It was funny, after my last couple of games, I was getting comments back about much tougher the combats seemed, PCs were actually getting dropped into negatives at least once per fight and there was a much bigger sense of danger.
At first I was worried that it would be too much for them and I would have a TPK, but my players adapted well. I'm also pretty generous in giving out appropriate level items to my players. If I had been stingier on magic there might have been more of a threat of a TPK, but its worked out very well for me so far.
PCs before were hoarding their dailies since they didn't need them and then would drop them all in the last fight before they took a rest and would just dominate. Now each PC is being forced to actually use one or two dailies per encounter. Also, the cleric player was thinking of playing something else, and the other players were encouraging him, saying they didn't even need a cleric. Now they are begging him to stay a cleric, or asking for someone else to play a leader.
I love it!![]()
Interesting read. I do something similar to the +5 per tier damage bonus already. I add half level bonus to monster damage, which surprise, surprise, by the end of the tier matches that exact damage bonus. It does work and has made the game way more dangerous. To compensate I have reduced monster hp to 75% which speeds up combat a bit and seems to maintain the balance.
Our group has talked about it and we decided to only try 1 leader in the next campaign as we should reach 30th level this summer - which is the end of a 2 year campaign.