It's great how short the attention span for a football fan is. From the start of the BCS championship game (1998) to 2002 (expansion was in the 2004 season), current ACC teams were in every single BCS championship game. In 1999 Florida State played Virginia Tech. So, acting like that conference is a pushover is not really in keeping with reality.
What did happen is the ACC added two programs (Miami and Virginia Tech) that were the best in the Big East, and this led to a logjam at the top and a more difficult schedule for all teams. While it did show us that they weren't as good as advertised, it also showed us what a impact SoS has on results. If you throw any WAC or MWC team in the ACC I'd be really surprised if they ended up with double digit wins... It's easy to look good playing nobodies, the hard part is to do it beating good football programs, of which the ACC now has several (Clemson, Georgia Tech, Virginia Tech, Miami and FSU).
The ACC expansion is a cautionary tale for any conference. I like seeing other conferences raise their SoS, but mainly because the results are easy to predict (I expected the ACC to struggle but not to the extent I've seen). If the SEC added the two best Big-12 teams people could be saying the similar things about them in a few years (although I do think the SEC is clearly better at football than the ACC)...