What they give you with the OGL is largely what can’t legally be copyrighted anyway, and in turn they saddle you with extra obligations.
The reason it seemed generous in the first place is that TSR’s prolific lawsuits poisoned the marketplace. The OGL was reassurance that Wizards won’t come for you if you make more content compatible with their game.
Most OGL gaming products could strip off the OGL label, reformat and change some names, and still be in the clear, per the EFF. The real question is if the chilling effect of the mere potential of lawsuits will stop people who would otherwise work in the field.
I imagine the answer is yes.
The author of that article appears to be the same lawyer who wrote the game Thirsty Sword Lesbians. They share the same name, at any rate.