Armond would likely be an upgrade over Cwynar.
Armond's 2010 stats: 43 TT, 21 UT, 6.5 TFL, 3 sacks.
Cwynar's 2010 stats: 30 TT, 9 UA, 2.5 TFL, 0 sacks.
Armond is 6'5'' 290 lbs v. Cwynar's 6'4'' 285 lbs.
A direct comparison of those stats is probably misleading, since Armond plays in a 4-3 and Cwynar plays in a 3-4. And who knows how productive Armond would be in a new system after having not played for a whole year.
Assuming all other obstacles are cleared (USC releases Armond to us, Armond passes the Faculty Board, etc.), I think the biggest remaining problem is how the team would react to letting Cwynar go in favor of a USC transfer. Cwynar already has two degrees from ND in hand, but I could easily see that upsetting some people.
As irishog77 just mentioned, there are also questions regarding Armond's genuine interest in ND and loyalty. Most of our players hate USC even more than we do; can you imagine one of them transferring and playing hard for our arch-rival?