Epic combat
The above is a thread I started which details my epic level party without expertise feats still hitting too easily for my liking (ie. I am in the "ban the feats, don't give anything in return" camp).
It's really dependent on the group, including the DM.
There are several factors involved:
1) PC design.
My wife was playing a Ranger and even with Twin Strike, she wasn't hitting a lot. So, I designed a sword and shield fighter for her that does a lot of close burst attacks. She has the highest to hit in the party, she has the highest AC in the party, and on many rounds she swings multiple times (sweeping blow / come and get it, etc.).
Suddenly, she loves her PC. She hits a lot because of 2 to 4 attacks many rounds combined with the best to hit.
She averages less damage per attack than the party Ranger (obviously) or even the party Sword Mage, but she's having a great time because she hits a lot.
Such a PC will become problematic at Epic level with the expertise feats (especially level 21 as per your link, the strongest relative level in the game system) because she is optimized for "to hit".
A PC like our Cleric who concentrates mostly on healing, has few area effect powers (hence, she typically gets one to hit per round) and the lowest AC in the party is a lot less of an issue at Epic with the expertise feats. She hardly ever hits and if she gets surrounded, has to waste time trying to avoid foes as much as she tries to attack them.
So, it really depends on individual PCs.
2) Which splat books are allowed.
When the PHP first came out, it was a lot harder to have a highly optimized PC and even harder to have a highly optimized group. Every time a splat book comes out, it becomes easier and easier to find feats and powers and classes and combinations that are just a tad bit stronger than previous books allowed. PHB II, for example, has 12 heroic feats alone that add a bonus to hit in one way or another (including expertise feats). Granted, many of them are extremely conditional, but it can and does add up. Combined with the synergies that new and different feats, powers, paragon path, racial, and epic destiny abilities bring to the table, it all adds up. This is generally not as true for monsters. Monsters are not getting that much stronger. The "math" was worse when there were fewer splat books. Something as simple as getting a reroll once per encounter on an attack roll adds an average of +3 to that attack roll.
3) PC familiarity vs. DM familiarity.
The players tend to play the same PCs day in and day out. Nearly every encounter can teach them a little bit more about each other and what works and what doesn't work.
The DM doesn't have this advantage. Nearly every set of monsters he brings into an encounter tend to be different with different strengths and weaknesses. As a general rule, I often go "Doh! I should have had the monsters arranged this way, or I should have done this instead of that". The learning curve for the DM is a lot steeper because his variables are changing every single encounter. There is also the issue of memory. I sometimes forget that a certain monster has a certain ability until it is too late precisely because this is the first time I am running that monster. "Doh! I should have used that power last round.". The players have this issue less since they eventually learn their PCs inside and out.
So I think there is a major difference between playing an epic encounter with PCs that the players are not as familiar with than with ones they are totally familiar with. The players familiar with their PCs will squeeze ever ounce of to hit bonuses out of their PCs.
The DM also has the issue of too much vs. too little. The players will often design their PCs to get a lot of "too much". If the DM does that, he could be begging for a TPK. For example, if the DM pulls in multiple monsters that stun, even if they are within the DMG guidelines for an encounter, a few bad dice rolls could spell trouble for the PCs. The players don't have this issue. The tougher they make their PCs, the easier it is for them to survive.
So getting back to the expertise issue, it is dependent on the group. Super optimized groups where many splat books (or Dragon magazine) options are allowed could easily get away with not having access to the Expertise feats.
Less optimized groups, groups that have access to less material, and/or groups where the DM is more on top of his game could use the Expertise feats and still be behind the 8 ball, even at Epic level.
