On the final issue of these series, I'll comment on the Warlock and its huge issues, and the Ranger, which is plain terrible.
The poor warlock doesn't really deserve to be left alone with a ranger. In fact, nobody does. That's why they are given animal companions.
Disclaimer: since writing this piece, I have played a bit more with warlocks and changed slightly my opinion on them. Despite their flaws, warlocks work really well in play. Better, in fact, than some classes I haven't judged so harshly. Nevertheless, they remain the most frustrating characters in the game to build and level up, each pact build feeling like a premade character, so much of what I said below stands.
These couple are, in my opinion, the most broken classes in the game. By broken here I don't mean power level (since Rangers are right there at the top), but design. Both the Warlock and Ranger suffer multiple, serious flaws that, in my opinion, detract from a fun play experience. The Warlock annoys me the most, since it actually has a lot going for it. Its set of class features is the best one in the game, being both fun and flavorful: the pact boons provide a nice minigame of cursing as many enemies as possible and collecting their death bonuses, while shadow walk cleverly compensates the low defenses and, together with prime shot, makes movement very relevant.
If only moving other ranged characters was half as interesting as the warlock! Sadly, several important flaws spoil what would otherwise be an amazing class. To begin with, there is the absolute lack of choice concerning at-will powers. This is most aggravating because all pact powers are awesome, yet you are forced to take the completely uninteresting Eldritch Blast. But it would be an issue even if the Blast wasn't as boring. The ability to actually choose an at-will power would make Humans the most appealing race for warlocks... if it weren't for the Multiple Ability Score issue, which negates that choice.
For a class that already has a reduced range of options, the split between Charisma powers and Constitution powers is devastating. Warlocks of a given pact look more similar to one another than any other class build in the game. Only Star Pact characters achieve some degree of diversity, but that's only because they are (unsuccesfully) struggling to have a playable power selection. This, added to the lack of variety in feats and equipment inherent to non weapon-based characters, makes building and levelling Warlocks a real pain. To be fair, playing them is still pretty amusing.
The same can't be said of the Ranger, which is without a doubt the most flawed profession in the Player's Handbook. The features are terrible, and the different builds laughable. Hunter's Quarry does its striking job, and the ability to wield large off-hand weapons is rather cool, but the rest is almost worthless. Melee rangers somehow gain Prime Shot, which isn't that useful for archers to begin with. And fighting styles are a joke: the only reason for an archer to ever pick Archery Style is to gain access to paragon paths.
I really, really hate ranger at-wills. It boils down to this: you have Twin Strike, and filler for the rare cases where TS isn't the best possible attack, such as having only one arrow left or losing your off-hand weapon. The problem is not that TS makes rangers overpowered (which it probably does, in some cases), but that it greatly reduces design space for at-wills, as it's almost impossible to make a damage-focused attack that is competitive with TS but not really overpowered. Come on, Careful Attack, the power that sacrifices strength for precision, is less accurate than TS, and would still be if its bonus was raised to +4. It doesn't help that all non-TS powers except sometimes Nimble Strike are useless.
The gameplay is as repetitive as it gets: spend encounter powers, use Twin Strike over and over. Positioning is more or less pointless, since getting a quarry is easy, and requires no upkeep. Archers could make an effort to use Prime Shot, but most of the time the best idea is to lock on a Quarry, then run away as far as possible, since bow range is virtually infinite on.
Still, there are some good things, such as the Beast Mastery build from Martial Power, which adds some very needed coolness without increasing power even more. I think the pet is a great idea, even if the implementation is a bit too complex for my tastes. At first sight, beast powers look slightly weak, but I'd have to see them in play to be certain. Another interesting contribution is the concept of hybrid powers that work on different ability scores depending on the build. While they have clunky wordings, they might be used to fix other classes that have different abilities for each build.
Next: The fixes start!