At this point, I'm not sure there is any easy way to remove the expertise feats from the game (though I have been having success in my current campaign doing just that). But everything I've seen still tells me that they were put in place to fix a perceived problem that was not actually the issue they thought it was, and they've instead ended up unbalancing the math more than balancing it.
I don't see it that way. I look at the vast plethora of hit points that monsters have at higher levels and see that players need every bonus that they can get to both "to hit" and "damage" in order to whittle down a monster.
The core math should just be balanced first, then riders and other abilities taken into account. Remember, the PCs have a lot more Encounter and Daily powers and abilities at Epic, but so do the monsters.
With the new damage equations, a first level monster does an average of 9 points (level+8) of damage against PCs with 20 to 30 hit points.
That means 2 to 4 successful hits and a PC is down.
29 levels later, most PCs have 4* 29 to 7 * 29 more hit points. Monsters do 38 points of damage (again, level+8). That means that monsters take out PCs in 4 to 6 hits. It takes one additional successful hit per tier for the monsters to take out the PCs at 30th than they did at 1st.
However, this assumes that the monster's chance to hit is identical which it isn't. It's actually better at higher levels, at least for NADs. And it assumes that damage is the only thing that matters which it isn't. Epic level monsters have a lot more riders than 1st level monsters.
Now when we go into the reverse direction, we see a similar thing. Monsters gain 6 to 10 hit points per level depending on role. If it takes 3 successful attacks by a non-striker PC at first level doing 9 points of damage to take out a foe with 27 hit points, it would take 90 points of damage per attack for that same PC to take out a 270 hit point 30th level foe in 3 hits at level 30.
PCs do not acquire 80 extra points of damage in 29 levels. That's gaining just under 3 points of extra damage per level and that doesn't happen. Non-striker PCs might gain about 30 extra points of damage over 29 levels (if that for some classes). So instead of killing the foe in 3 successful hits, it takes 7 (or more) successful hits.
Sure, there are buffs and such in the game system that allow for a better chance to hit, but with the core rules dropping 20% from the to hit, it's really tough to increase the hit chance enough and the damage enough for the PC to take the foe out in 3 hits still if one doesn't include Expertise.
So, the basic damage math of PCs at the higher levels is about a third to a half of what it is at first level, even assuming that the PCs can gain back the -4 to hit. They then need strong damage buffs as well.
The higher level grind issue has not gone away. It's just been mitigated a bit by Expertise and by the fact that increased monster damage means that the DM can throw weaker monsters at the PCs and still challenge them the same as before.
As encounters get longer and longer round-wise because of grind as PCs level up, the monsters have more rounds to throw on more riders (the damage is mostly irrelevant because there are more rounds, but the monsters need more rounds to do the same relative damage, i.e. they are doing a lower percentage of the PCs total hit points per successful hit, 30% to 50% at level one, 15% to 25% at level 30). And this (and the increased number of ways to self heal) is why leaders are needed less for healing as levels go higher, but might be needed more to hand out free saving throws or buffs to saves.
PCs, on the other hand, also require more rounds to take out the monsters as they level up. So, this is only mitigated by the PCs doing more dpr and that means having more strikers in the group. The PCs do not acquire enough extra hit points of damage per level with powers, so they need to do it with strikers (or with controllers that can hit a lot of enemies with a single attack).
The effect is gradual. But even in our mid-Paragon campaign (and having a lot of strikers in our group), we have dropped from 4 encounters per 5 hour session at low heroic down to 2 encounters per session at mid-Paragon. The monster total hit point math is what it is and no number of extra powers are going to change that unless the PCs do a ton more extra damage to permanently take out foes. An extra die of damage for an Encounter power or two extra dice for a Daily don't make up for the sheer number of extra monster hit points.