It also means that you're tied into accepting a lot of decisions which you might not agree with, from the size and impact of feats, to the names of the various ability scores and skills.
Well that's not true at all. You are free to use, mangle, fold, rename, rework, or otherwise change any aspect of OGL material you want to work the way you want for your own product. You just have to give credit where credit is due for where you got your work.
Likewise, OGL material does not have to be d20 material. Fate and Spirit of the Century for instance.
Personally, I don't buy anything that's OGL, but I would buy an OGL-inspired product of the same size and quality for the same price. That it's entirely self-contained within the one book, and doesn't require or allow outside reference, is a huge selling point for me.
That does not make a lot of sense as a complaint to me. There are plenty of OGL books that are self contained. When you use a feat, rule, what-have-you, from another source, you can port whatever you want into your own book. Its good form to give a head's up to where the original stuff came from, but I don't know that many OGL books which actually require you to buy all the original source material. Whether a book requires outside references has nothing to do with being OGL.
To make clear what I am saying, Take for instance a monster. If I want to port a monster from say the 3.0 Creature Collection (A thing I have done) into a Pathfinder compatible product, I can alter the base stats however I want, and name it whatever I want (in fact with Creature Collection you have to rename it as the names are not Open), and can change it however I deem appropriate. I can then include the entire monster writeup (and the monster writeup does have to also be different if you use CC as its not open either), stats, description, et.al. in my book. I then just reference in my copy of the OGL where I got the idea. I don't have to even identify what the changes are that I made to the creature, nor what I renamed it. Just use it however I want.
Likewise, for a Yakuza book I wrote, I referenced some feats from another book on magical tattoos. I actually reworded the feats somewhat and included them in my own book. But I still gave credit to the book I got my ideas from in the OGL. But you could buy and use my Yakuza book without ever buying a copy of Inkantations (or even the Book of Erotic Fantasy from which they derived some of their ideas).