I dunno. Starlock is certainly a finicky kind of class, but honestly its not as MAD as people make it out to be. You just have to knuckle down and realize you aren't going to be able to use both the CHA and CON based powers. You're going to have one at-will that's worth using and a lot of the supposedly star pact based powers are not going to be good choices. You still have a whole slew of choices. If you go CHA intensive then you're going to select a lot of "fey pact" choices or you're going CON intensive and picking a lot of "infernal pact" choices.
At that point the starlock really is no worse off than plenty of other classes which have their choices of class powers limited to some extent by ability score allocation. There are still a WIDE variety of choices. The MAD issue only exists if the player isn't clever enough to realize that its impossible to make one starlock that can use all star pact powers well. Nor are they worse off in terms of NADs, they'll have a good INT and thus getting a good stat boost to AC and Ref, and either a good boost to Fort or Will, which is really the same as anyone else. Make CON/CHA your third best stat and boost it now and then, you won't be in bad shape. All riders are INT, so that isn't an issue.
I'd say the main thing with the starlock in my game is he has decent defenses, they are just all not top tier. Considering he's concealed practically 100% of the time when he gets attacked it isn't effectively a huge problem.
The issues I see are more like there aren't a lot of interesting build options in heroic tier, the warlock is pretty picky about equipment, and its not a class that you hand to newbies and have them be terribly successful at. Overall if its built right and you get one or two key items then you're very much competitive with everyone else. Lets face it though, every class eventually runs into that "I need certain items to excel" thing. It just happens a bit later for melee classes (they need IAoP and a damage boosting weapon) etc.
ALL of the classes in retrospect could have been tweaked here and there, or the vast majority anyway. If I were "fixing" warlocks all I'd do is give them some decent heroic tier feats and repair the awkward at-will situation. That would make them more interesting and possibly a tiny bit stronger.