What’s the mathematical equation for number of players in the cut? That’s a great way to save on time. I don’t think 5 rounds for a 25-32 person Regional is too much. And if the cut is Top 4, that seems pretty reasonable; 12%-15% of the attendance making the top cut seems just fine in determining the best players.
If the day isn’t going great and by round 4 or 5 you know can’t make the cut and are sick of losing, it’s not the end of the world to just drop from the lower tables. Or, if you’re there to play Netrunner because you enjoy the game and play in tournaments to get good competitive games (or more practice to get better), having more rounds of Swiss means you have more rounds where the structure pairs you against someone of equal skill, since it takes a few rounds to get enough past the random factor.