I too liked the old-school look the 3.5 DDC's have, but I can certainly understand GG wanting to update it for 4E. I suspect the adventure content will still be just as cool.
I haven't tried 4e. I've heard it is more akin to a table top mini game, which the people saying it seem to be using as a negative, but it is the one thing that intrigues me about it. RPGs are simple, you keep the mechanics of combat straightforward, and the rest is the DM and the players having fun with their characters. That kind of roleplaying doesn't do much for selling tons of rulebooks, which is why they kept tinkering with the system. But the adventures are what people remember, and what are so handy to have as a DM.
Unfortuneately the artwork is a big thing. Sometimes players just need to get their visualization skills kickstarted. I can write new flavor text, but I can't do any of the artwork, so I wish that Dungeon Crawl Classics had been left with classic artwork. Why not just use the new art in a different line of products and keep the old style art with DCC? Ah well, another topic of discussion.
If you can't get the modules themselves I'd advise anyone looking for that classic style to download the pdfs before they are yanked. But I just don't see how pdfs of old modules can effect the sales of 4e in a negative way. I think the opposite would be true.