This post is a response to one section of Samhaine's latest post, so go read that first. I'll wait. You're looking for the "I Won this 18 in the Lottery" section.
Maybe there is a middle ground between randomly generated ability scores and point-buy ability scores that gets it all right. The appeal of random generation, to me, is that they feel "earned" (won, really) snatched from the jaws of doom. This is great and all, but... people lose that lottery all the time. A feeling of winning, of course, needs a threat of loss in order to exist, but boy does it suck when you lose the ability score lottery in games. (Admittedly, some of us lose the ability score lottery in real life; just ask some of my friends about their real-life Con or Dex scores, and whatever my theoretical Int is, I run mad with envy when I'm around people who have higher. Regrettably, this is common.) I have played characters who won the ability score lottery and characters who lost it, and I didn't find that playing with crappy ability scores improved the roleplay; I categorically reject that old-school argument. Having "a weakness" is well and good; having "nothing but weaknesses" is not.
I have my problems with point-buy, though. In 4e, you're never going to see a fighter with high Int, unless the player deliberately created a grossly suboptimal character. Pretty much everyone is going to have an 18, 19, or 20 in their class's attack stat. I've played a character who started with a 17 in his attack stat. I don't recommend it, and wouldn't repeat the experience. (My issues with non-Essentials star pact warlocks are pretty serious, but not the point of this post.) My complaint about ability scores all being the same within a party comes down to Syndrome's argument in The Incredibles.
The one piece of good news here is that +2 to your attack stat is trivially easy to come by (if all else fails, play a human); the downside to that is that it sets up a situation where some races just never have members of certain classes. Deva fighter, anyone? This is balanced somewhat by giving otherwise undesirable race/class combinations some grossly OP feats, which then come back to bite the system in some really odd ways. (My issues with Dwarven Weapon Training are also not the point of this post, but I can point to dwarf-flavored revenant assassins as part of my issue. Thank you, Kainenchen, for being a good sport about that.)
Disclaimer: I freely acknowledge that the solution I'm about to propose may simultaneously not solve the problems of point-buy while also losing the lottery feel of random generation. I don't know if I would like this system, because I haven't thought it out yet.
What if you randomly selected between different ability score blocks? Something like the following table, modified from the 4e PH:
Introduce some or all of the following iterations on this system, seasoning to taste.
1. Deliberately unbalance the stats somewhat, within a range of 2-4 point-buy construction points, possibly buffering whichever of these stat blocks you as a GM find to be least desirable.
2. Minmax slightly more than the core rules allow, so that there are some ability scores below 8, or stat blocks with two 8s. Because players have lost some of their choice here, it's more fair, not to say more desirable.
3. Create versions of these stat blocks that are pre-arranged, and do not allow players to arrange to taste. You could get away with higher overall scores this way, if you wanted. To water this option down very slightly, allow players to switch the positions of two and only two scores.
4. Using the PH2 as-released version of Weapon Expertise and Implement Expertise (the +1 attack bonus per tier feats), add the following: You may not have an ability score higher than 17 at 4th level, 18 at 8th, 19 at 11th, 20 at 14th, 21 at 18th, 22 at 21st, 23 at 24th, or 24 at 28th. (To state this another way, you must not have had an ability score higher than 16 at character creation, after racial modifiers.) This is a feat tax on those characters, but because their points are spread out elsewhere, they do at least have a material advantage in skill-use situations.
Variants 1-3 bring a little more lottery back into ability score generation, and are only fair because the player doesn't control what they get. Could this lead to players being unhappy? Maybe, but I think that a lot of players would still see the manifest equality of their stats and not make too much of a fuss.
Edited to add: So there I was, poking around in recent back articles of a blog much, much more widely read than this one, and I find that he too has referenced Syndrome from The Incredibles as part of an argument about ability scores. I would like to state for the record that I had not read the linked blog post before writing this one, though I had read this closely-related post.