There are many good ideas mentioned here and, whatever happens, I do hope Topps acknowledges the 50th of Wackys in some way. Off the top of my head, here are a few things I'd love to see.
*A book that highlights the history of Wackys. I think it might be something that is probably more for a hard-core fan, but looks at all aspects of Wackys: the artists behind them, the business side, the collector frenzy from the 70's, the licensed products, fan recollections, etc. Perhaps something along the line of books that have looked at, say, the history of Marvel comics.
*Some kind of card/sticker set. It's the cards/stickers that started it all in the first place. I'm not sure what format I'd want to see, but something that manages to both catch the spirit of the original 2-stickers-in-a-pack yet with a unique spin.
*Any sort of fun, licensed products. I was in Walgreens yesterday and saw little boxed GPK vinyl figures. Didn't buy one and I couldn't quite tell what the figures looked like, but I'd love to have some of the classic characters (Weakies, Plastered, Cap'n Crud, etc) in three dimensional glory! And that's just one idea but spin-offs, but I do like expanding my Wacky collection beyond stickers/cards alone.