4e monsters with a lot of hit points can generally bring the pain.
I think I mentioned a recent hydra fight upthread. The PCs, in the first three or so rounds of combat, delivered about 500 points of damage to it, and took out one of its three salamander guards and bloodied the other two on the way there. Those 500 points were enough to take out two of its four heads, and at each point they were able to use cold damage to stop it growing two new heads instead.
But - having shaken off the various dazing, blinding and other action denial/debuff affects on it (I am using a combination of the MM and MV Many-headed traits, and applying them to blindness also, to give my hydra a chance against my action-denying party) - it was able to actually spend an action point on its turn for useful effect, getting 6 attacks against the fighter - four bites for 4d10+10 and two fire breaths for a bit less than that. And it dropped the fighter from 105 to -62 (just above -ve bloodied) with those attacks.
The invoker was able to slide the fighter out through a temporary teleport portal, and he will be healed to consciousness but probably unable to rejoin the melee combat. The paladin, with better AC (plate rather than scale, heavy shield, and meliorating armour one milestone into the day), will probably fare better, but is also wondering how long he'll be able to hold off the hydra onslaught! And it still has an action point unexpended.
There is no doubt in my mind that solos with some ability to handle action denial can bring the pain!
Tables with high acument players who optimize their PCs and group synergy will need even higher than L + 1 or L + 2 as remedial/entry encounters.
<snip>
HP inflation has little (or nothing) to do with PC potency/survivability in 4e. As we just outlined, its activatable abilities (DR and temp HPs) and negative status effect/action denial that wonks the action economy of monsters and BBEGs.
<snip>
If you're going to rein in PCs survivability, its not their HPs that need adjusting downward, its the breadth and potency of their deployable resources (or you have to do it by proxy of buffing monsters...the "more fun" way to do it).
This fit's with my experience too. My PCs just reached level 18. They are on their sixth encounter since the last extended rest - they started the day at level 17.
First there was a level 18 encounter against two 22nd level Death Giants and a level 17 Eidolon. This also involved the invoker spending a healing surge for a Knock ritual. On the whole, an easy encounter.
Then there was a level 21 encounter against a 19th level solo Beholder, a 17th level elite Beholder Eye of Flame, and a 15th level elite Roper. The terrain for this fight was incredibly punishing for the PCs - a chasm with a 200' drop to an underground river, that the Beholder pushed both ranged strikers into. (Amusingly, after being knocked back down again after making it most of the way up, the ranger ended up killing the Beholder with twin strikes shot while standing on a ledge next to the river.) I described this combat in more detail
here. This encounter got the PCs up to 18th.
Then there were three minor encounters - a single fungal hazard dealt with by the ranger while expanding an overgrown, abandoned duergar farm, and a couple of skill challenges. The first, which had been commenced back at 17th level and involved navigating through the underdark, failed, and the PC fighter ended up falling through thing stone into the underground river the duergar had relied upon to irrigate their fungi. This then triggered another skill challenge for the party to recover the fighter and regroup successfully in the river, and they succeeded at that.
Then, for a couple of reasons, they proceeded further downriver (on Phantom Steeds) to where they encountered the hydra. So far they have been dealing with this as a 21st level enounter - 18th solo hydra and 3 16th level salamanders, one elite. But reinforcements are now arriving - two 17th level salamander archers, and 4 archons of 17th and 18th level, which will take the level of the whole encounter up to 23. For a party low on surges and dailies after the punishing fight with the beholders, this may be too much - I am anticipating a possible retreat downriver. But they have pulled off pretty surprising victories before, so it's a bit too early to judge. (If they kill the hydra, they may also try to cow the elementals into submission.)
It's not hard to create a real sense of threat and drama in 4e - you just have to use the tools at your fingertips (and, in my experience at least, generally widen your encounter, in terms of numbers of foes, rather than just upping the level, which can make the maths grind if you're not careful).
"See, see, 4e isn't balanced either...you have to fix stuff at Paragon and Epic tier." Yes, I agree, as power and resource breadth proliferates, 4e does get more "unwieldy" (just as in prior editions).
<snip>
The game-breaking deployable resources are siloed within high level Rituals and, even then, are considerably less punitive toward game scope (Exploration and Social) functionality (Phantom Steed notwithstanding).
Phantom Steed is very strong, and I can see how in an exploration-oriented game you'd probably just want to ditch it altogether.
But I haven't found paragon hard to GM at all. The tools are powerful and, for me at least, easy to use. I'm told that epic is harder because the players' action denial abilities grow almost without bound. If that turns out to be so, however, I think I'll be able to handle it by building solos more carefully, and by doing the same thing as I do now: more foes, less rest, more pressure.
