Ears14U: A 30% discount on an already ancient game sure doesn't make me jump on them also. Have you noticed that GOG just keeps rotating the same old shit over and over again? I would think they would put nearly everything on sale. At least that's how I would put up a great sale.
I actually grabbed a few games finally, but yeah, the discounts on some of the titles just aren't there. Not that I don't think some of the games are worth the money - I do. But my backlog is so enormous that it's stupid of me to buy a game I won't play right away unless the discount is pretty big.
As far as the games on sale go, I imagine this has to do with publisher agreements and isn't a carte blanche decision by GOG. The real issue is the sale dragging on too long if it means recycling the same games on offer 4 or 6 times.